History Main / FanficFuel

** After the ComicBook/New52 reboot, what happened to Wally West and the other speedsters was a hot topic for fanfic. Though eventually, ComicBook/DCRebirth and [[ComicBook/TheFlashRebirth Josh Williamson's Flash run]] would later provide canon reintroductions for them, it still created an avenue for Canon Divergence fics.

* ''ComicBook/{{Excalibur}}'' #74 has Mister Sinister gloat over acquiring the DNA of Rachel Summers, and this is never brought up again. What could he possibly have in mind, and why hasn't he done it already?
* ''ComicBook/FantasticFour'': During the 90s, [=Tom DeFalco=]'s run introduced Jonathan Richards, known as Hyperstorm, the son of Franklin Richards and Rachel Summers from an alternate version of ''ComicBook/DaysOfFuturePast''. Hyperstorm was sent to a dimensional void with Galactus, who returned. Hyperstorm was never seen again. In six chapters of five thousand words or more, describe Jonathan Richards growing up in his own timeline before becoming a villain, how he returns from the dimensional void, what he plans to do in modern day, how he defeats the X-Men and the Fantastic Four at the same time, and how he fights in ridiculous energy battles versus Rachel Summers, Hope Summers, and maybe Nate Grey, or Vulcan, he hasn't done a whole lot lately. Just like KRPBLRRR BLRPSHKRR like explosions everywhere.
* ''Franchise/TheFlash'':
** After the ComicBook/New52 reboot, what happened to ComicBook/WallyWest and the other speedsters was a hot topic for fanfic. Though eventually, ComicBook/DCRebirth and [[ComicBook/TheFlashRebirth Josh Williamson's Flash run]] would later provide canon reintroductions for them, it still created an avenue for Canon Divergence fics.

* ''[[Franchise/{{Firefly}} Serenity]]'':

* ''ComicBook/{{Serenity}}'':

** There’s a big gap between "All New Firefly" and ''ComicBook/FireflyBrandNewVerse with room for a lot. Primarily, Fans have wondered what happened to Mal in the gap that led to him being absent apart from a brief DrowningMySorrows shot.
** And what took Mal from being eager to fight in ''ComicBook/NoPowerInTheVerse'' to living like a hermit in ''Return to Earth-That-Was''
** Also from "All New Firefly": How the “mudders” would react to Jayne dying, assuming anyone still saw him as heroic at all after “Jaynestown”.

* A sizable genre of ''Podcast/TheMagnusArchives'' fanfiction is "Scotland fic" -- namely, fanfiction that covers the three-week TimeSkip between Episodes 159 and 160 that [[FanPreferredCouple Jon and Martin]] spent in a safehouse in the Scottish highlands. The popularity of these fanfics can be attributed to two main reasons. One, because Episode 160 was followed by a six-month hiatus, during which the show surged in popularity. And two, because the end of Episode 159 heavily implies that [[spoiler:they're now an OfficialCouple]], which Season 5 makes explicit.

* A sizable genre of ''Podcast/TheMagnusArchives'' fanfiction is "Scotland fic" -- namely, fanfiction that covers the three-week TimeSkip between Episodes 159 and 160 that [[FanPreferredCouple Jon and Martin]] spent in a safehouse in the Scottish highlands. The popularity of these fanfics can be attributed to two main reasons. One, because Episode 160 was followed by a six-month hiatus, during which the show surged in popularity. And two, because the end of Episode 159 heavily implies that [[spoiler:they're now an OfficialCouple]]; WordOfGod has confirmed this, and stated that it will be more explicit in Season 5.
[[/folder]]

* In Earth-3490: ComicBook/CaptainAmerica married [[ComicBook/IronMan Iron]] [[GenderFlip Woman]] and thereby prevented the ComicBook/CivilWar. So how did Natasha Stark become Iron Woman? How did this affect team dynamics? [[{{Lemon}} What was the wedding night like?]]

** Around the time of the ''ComicBook/CivilWar'' crossover, the series introduced a new breed of ''good'' [[HumongousMecha Sentinels]] that actually came with cockpits and pilots, making them just as effective against Mutant threats, but without the possibility of them [[TurnedAgainstTheirMasters turning against their masters]]. Even though the writers generally kept the Sentinel pilots as side characters, they could have provided the ''perfect'' setup for a good old-fashioned [[MechaShow mecha series]] set in the Marvel Universe. Just imagine a classic scene of Magneto squaring off against a Sentinel--but told from the ''Sentinel's'' perspective.

May lead to {{Continuation}} or FanSequel. See CanonFodder, a subtrope where these scenarios actually get addressed in the work, or the creators at least imply that they intend(ed) to tell these stories themselves at a later point. See also FandomSpecificPlot, where specific fanfic scenarios become popular among fanfic writers. Can overlap with FixFic if it's a particularly hated episode or AudienceAlienatingEnding the fans are trying to rectify to their liking.

* ''ComicBook/Serenity'':

May lead to {{Continuation}} or FanSequel. See CanonFodder, a subtrope where these scenarios actually get addressed in the work, or the creators at least imply that they intend(ed) to tell these stories themselves at a later point. See also FandomSpecificPlot, where specific fanfic scenarios become popular among fanfic writers. Can overlap with FixFic if it’s a series ending the fans are trying to rectify to their liking.

* ''Literature/TheCosmere'': There are still six PiecesOfGod whose identity and intentions remain unrevealed, there are large gaps -- sometimes thousand of years -- between various books and a lot of fan-favourite characers are long-lived [[PlanarChampion worldhoppers]], not to mention that there's an entire city floating in space that's occupied solely by worldhoppers. Prime fanfic fuel material.

[[folder:Film — Animated]]
* The ShowWithinAShow in ''WesternAnimation/{{Bolt}}'' could spawn dozens of fan stories.
* ''WesternAnimation/TheBookOfLife'':
** How Chakal got the medallion from Xibalba was glossed over, so are the details of how the Lands of the Remembered and Forgotten work. In fact, just the Land of the Forgotten itself.
** The reveal through WordOfGod, that there are a few other afterlives, like the Land Of The Unknown and the Land Of the Cursed as well as revealing that La Muerte has a twin sister, La Noche, who rules the Land of The Unknown, and that Xibalba has an older brother, who rules the Land of the Cursed, a hell like domain. Can probably fuel fics, for a long time.
** All of the information that Jorge shared through Website/{{Twitter}} could be this.
* ''WesternAnimation/TheBossBaby'': At one point during his visit to Baby Corp, Tim asks the titular Boss Baby why he doesn't remember his time at the company, and the Boss Baby mentions that all babies who work there forget all about it once their company pacifiers are taken away. This provides fanfic writers plenty of opportunities to explore what Tim's time at the company might have been like before the events of the movie.
* In ''WesternAnimation/{{Coco}}'', even though [[spoiler:Ernesto de la Cruz]] is exposed as a murderer, who's to say that he doesn't have at least one LoonyFan who'll put up an ofrenda for him and enable him to cross over?
* ''WesternAnimation/{{Frozen|2013}}'':
** The cameo by Rapunzel and Eugene during "For the First Time in Forever" has launched a number of ''WesternAnimation/{{Tangled}}'' crossovers.
** Elsa and Anna are canonically RoyalsWhoActuallyDoSomething, a higher proportion of ''Frozen'' fanfics are {{Government Procedural}}s compared to most other fandoms, with the sisters and Kristoff tackling inner workings of Arendelle's government.
** The questions that the movie leaves unresolved:
*** Where did Elsa's powers come from? Does having a ruler with magical powers affect Arendelle's international relations?
*** Is Hans the Black Sheep of his family, or are the rest of the princes from the Southern Isles AlwaysChaoticEvil?
** Are there others like Elsa, and if so, will she ever meet them?
** WordOfGod revealed the reason for Elsa's powers was going to be included in the film (being born during a millennium of a certain alignment of Saturn) but was cut for time and plot relevance. While the canonicity of this proto-canon can be considered debatable (could be related to the winter solstice birth thing or may even be retconned in the sequel), this is even more Fanfic Fuel, such as the possibility of others with magic powers being born at certain year intervals and/or alignments, or even who the cryokinetic "previous-1,000th year Saturn alignment" before Elsa was -- perhaps the original Snow Queen from the original fairy tale? [[WesternAnimation/FrozenII The sequel]] gave some more explanation for how she got her powers ([[spoiler:it's implied they were a reward for [[StarCrossedLovers her Northundra mother saving her Arendellian father's life]]]]), but it's still open for further exploration.
** Given the fact that both Elsa and Anna are separated from each other for 13 years and have now just been reunited at the end of the movie, a story about how the two sisters adjust their life together and rebuild their strained bond is a very common premise for many post-movie fics.
* In ''WesternAnimation/Home2015'', now that Humanity has a fellow population of aliens both on Earth and the Moon who are likely sharing all their advanced technology such as interstellar space capability, what happens to Earth's society now (especially with [[spoiler:all other aliens coming to Earth to party as well]])?
* ''WesternAnimation/InsideOut'':
** The premise of the movie, with everyone's minds being some sort of control center manned by five characters representing five emotions (Joy, Sadness, Anger, Fear, and Disgust), poses a question, what would the inside of your favorite fictional character's mind look like while following the movie's rules? Who would their dominant emotion be? What would their core memories be?
** For the movie itself, we have how Riley's emotions carry her through her teenage years.
* Tai Lung in ''WesternAnimation/KungFuPanda'' has gotten plenty of fanfics about what happened to his real parents and how he ended up adopted. Po got the same treatment until ''WesternAnimation/KungFuPanda2'' revealed his origins.
* ''Westernanimation/TheLandBeforeTimeVIITheStoneOfColdFire'': The rainbow faces are strongly implied to be [[AncientAstronauts aliens who came to blend]] [[AlienAmongUs in among the dinosaurs]]. There are many fanfics that explore what their civilization and culture may be like, and what their motivations are.
* ''WesternAnimation/LiloAndStitch'':
** Long before there was ever [[WesternAnimation/LiloAndStitchTheSeries a series]] to take up the idea, writers had 623 blank spaces[[note]]Experiment 621's appearance in the UsefulNotes/PlayStation2 video game ''Stitch: Experiment 626'' and later major character Experiment 625/Reuben's appearances in prequel comics shown in ''Magazine/DisneyAdventures'' prevent this from being 625.[[/note]] to fill in with fan characters, a vaguely-described laboratory for them to be born in, and a universe for them to explore. They made sure to take advantage of this.
** Considering that, one, most of the canonical experiments remain yet to be seen to this day, and two, experiments ''after'' Stitch have been made in [[Franchise/LiloAndStitch the franchise's]] canon, there are still going to be plenty of [[SailorEarth fan experiments]] for years to come.
* ''Franchise/TheLionKing'' has a lot of this.
** For starters, the movie's {{Leitmotif}}, the neverending Circle of Life, means that you can write sagas of the royal lion family. Then, there are lots of characters that were introduced but not developed in comics or books, like Ni, Tama, Tojo. Also there are many story gaps that fanfic writers love to fill, like the years of Scar's reign (or his [[InformedAttribute supposed]] relationship with Zira), or where the Outlanders from the second movie came from.
** Then there's the fact that [[spoiler:Scar's GoryDiscretionShot shows him going down fighting, forecasting HesJustHiding with a chance of EvilCripple]].
* ''WesternAnimation/{{Minions}}'': The prologue shows just a few examples of who Minions served in the past. What other historical figures did they serve as well?
* In ''WesternAnimation/{{Moana}}'', what did Maui mean by “not since I ripped off (Tamatoa's) leg”?
* The ''WesternAnimation/{{Mulan}}'' sequel did nothing to curb this. In fact, there was enough FanWank generated for several [[BetterThanCanon attempted rewrites]]. The first movie itself contains a TrainingMontage covering countless little interactions, Mulan's family dealing with their only daughter [[InHarmsWay out of sight in the army]], the Huns moving in to [[OffscreenMomentOfAwesome massacre the Chinese Army at that village]], and of course that one line:
--> '''Mulan:''' (''to Shang'') Would you like to stay for dinner?
* Tooth's line from ''WesternAnimation/RiseOfTheGuardians'' that the guardians were all someone before they were chosen gives rise to fics about their origins that may incorporate or disregard their backstories from [[Literature/TheGuardiansOfChildhood the books]] the movie is based on.
* ''Franchise/ToyStory'':
** Though the finer details were left intentionally vague, plot points in ''WesternAnimation/ToyStory2'' seem to establish that Woody has "lived" for around [[OlderThanTheyLook fifty years]], leaving a huge gap in his backstory that could explain how a coveted antique toy wound up in Andy's possession (or, for that matter, why Woody doesn't seem to be aware of the fictional character that he's based on).
** Speaking of ''WesternAnimation/ToyStory1'', what would your toy collection coming to life be like?
* ''WesternAnimation/TurningRed'':
** Ming Lee's childhood, the early days of her relationship with Jin, and [[spoiler:her struggles with her red panda form]] has been the subject of several fanfics.
** What kind of adventures Mei will get up to post-movie now that she's permanently a red panda shape-shifter is quite popular to write about.
** Though the idea of [[{{Animorphism}} animal-based shapeshifting]] isn't explored beyond Mei and her family, the concept is popular enough that fans have expanded upon it by introducing [=OCs=] with similar abilities to Mei or giving Mei's friends their own animal forms.
** Lots of fans love to speculate on precisely why Ming is so adamant that Miriam is "odd" and a poorly chosen friend for Mei, with reasons ranging from Ming being unconsciously racist (believing Miriam's "oddness" stems from her race or religion) or classist (assuming Miriam's dress habits derive from a lack of familial funds, which could make her a potential platonic GoldDigger) to [[DisproportionateRetribution resenting Miriam for being Mei's first friend and thus "stealing" her away from Ming]]; some of these also have Miriam [[WrongAssumption assume that her race or religion is the reason only for Ming]] [[EveryoneHasStandards to respond with shock at the idea and reveal the reason to be something else entirely]].
* ''WesternAnimation/WreckItRalph'':
** How many other video game bosses also attend Bad-Anon, and what problems are they having?
** For ''WesternAnimation/RalphBreaksTheInternet'': What do the websites on the Internet look like from the perspective of Ralph and Vanellope that weren't shown in the movie, and what goes on within them?
* ''WesternAnimation/{{Zootopia}}'':
** Given that [[spoiler:Nick becomes Judy's partner on the force]] at the end of the film, there are a HUGE number of PoliceProcedural Fics that have the two of them solving various crimes around the City. And given the MaybeEverAfter relationship they had at the end of the film, it's not at all uncommon for these to also involve heavy amounts of {{Shipping}}.
** The titular city is inhabited only by terrestrial mammals. Lots of fans have had fun coming up with other cities in the same world to accommodate birds, reptiles, amphibians, and marine mammals.
** The film also has plenty of [[WhatCouldHaveBeen/{{Zootopia}} scrapped concepts]] that fanfic writers use in different ways:
*** Originally the film was to centre on a spy rabbit called Jack Savage. Now, Savage has no end of fan art, and appearances alongside Nick and Judy in various capacities in fanfics. Frequently seen in many of these fics is a fox character named Skye, who originated from a bit of art from the "Jack Savage" draft, and is often used by fanfic writers as a partner or love interest of Jack's.
*** After the Jack Savage draft was dropped, the creators moved on to a considerably DarkerAndEdgier version of the final film that had Nick as the protagonist, and had predators forced to wear shock collars. Naturally, fanfic writers have been keen to make AU fics about what this version of the film might have been like. Some other fics try to find ways to bring either specific concepts from this version (like the shock collars) or characters that didn't make the final draft (like a ConspiracyTheorist badger named Honey or an antagonist pig Mayor named Swinton) into the same universe as the final film.
** Then there's Nighthowler and its effects, especially with the revelation that prey ''can'' be affected by the toxin.
[[/folder]]

* ''FanficFuel/MyLittlePonyFriendshipIsMagic''
* ''FanficFuel/Supermarioglitchy4sSuperMario64Bloopers''

[[folder:Western Animation]]
* The final episode of ''WesternAnimation/{{Amphibia}}'' drops multiple ones:
** Ivy mentions discovery of a new continent "untouched by frog, newt or toad hands", with at least 3 characters, [[spoiler: Sprig, Ivy and Grime]] eager to explore it. It's a perfect setup for all kinds of crossovers.
** Anne, Sasha's and Marcy's lives after the series' finale, either leading towards the WhereAreTheyNow ending or going forward.
** The fact that Anne[[spoiler:, upon dying at age 91, will become the replacement of the omnipotent GuardianOfTheMultiverse, basically becoming a god]].
* ''WesternAnimation/AdventureTime'':
** The history between Marceline and Simon Petrikov. As the show went on, it's clear that Simon's morals and ethics were a heavy influence on a young Marceline, serving as a ParentalSubstitute. Fans enjoy exploring their bond, coming up with stories that either take place in the immediate aftermath of [[AtomicHate the]] [[WorldWarIII Mushroom]] [[ApocalypseHow War]] (which is this trope in of itself) or take place after Simon is returned to normal in present-day Ooo, to nothing of the various AU fics where he at least makes an appearance as a mentor figure.
** For that matter, the relationship between [[spoiler:Simon and Betty]] seems to get a lot of attention.
* In the ''WesternAnimation/AladdinTheSeries'' episode "Eye of the Beholder", it's revealed that Fasir and Mirage were once in love. What was their past like?
* ''WesternAnimation/AvatarTheLastAirbender'':
** The fate of Ursa. The show left a few other minor plot threads hanging, but that's the one that really got everyone upset, and speculating. It was resolved in ''ComicBook/AvatarTheLastAirbenderTheSearch'', though it [[BrokenBase divided]] fans and critics.
** And, you know, a century-long war, with plenty of rich, undeveloped ground for exciting battles and stuff. And one thousand Avatars in the history of the world, too.
** The SequelSeries, ''WesternAnimation/TheLegendOfKorra'', is filled to the brim with potential fanfic hooks. Not only is the show set eight decades after ''WesternAnimation/{{Avatar|TheLastAirbender}}'', but there are also several smaller {{time skip}}s within the show itself, including a whopping 3-year gap between Books Three and Four. Also, ''Korra'''s comparatively faster pace means that a lot of background details that aren't directly relevant to the plot are left open-ended, including [[WorkingWithTheEx the specifics of past relationships]], the exact details of villains' [[MysteriousPast rises to power]], and [[SequelNonEntity even the fates of some of the main characters of The Last Airbender]]. Considering the creators are [[TeasingCreator well aware]] of how their show's fandom operates, this is almost undoubtedly intentional. In fact, in the Book Four commentary, they told people to write fanfic about Mako's relationship with Zuko's granddaughter because they couldn't fit her into the show.
** Another example for ''Korra'' is alternative starting points for Korra and Asami's relationship. In Book One, Asami's father is an Equalist, an anti-bending revolutionary. A popular fanfic origin is one in which Asami fully serves them rather than turning on her father and siding with Korra. This generally involves Asami attempting to seduce Korra. A similar situation occurs with Korra having been captured by the Red Lotus as a child, at which point she and Asami are on opposite sides for a different reason, until they inevitably find each other.
* Since the ''WesternAnimation/{{Beetlejuice}}'' cartoon has an almost completely different premise than [[Film/{{Beetlejuice}} the movie]] did, one of the most common sources of fanfic fuel involves figuring out how the cartoon versions of Beetlejuice and Lydia met and became friends. (There ''is'' a vague back story given in [[ComicBook/{{Beetlejuice}} the comic book adaptation]], but it's unclear whether this is intended to be canon to the show.) The other question fic writers like to try to answer is, in the absence of a proper series finale, what became of the duo's relationship in the future?
* ''Franchise/Ben10'':
** There's plenty of AllThereInTheManual information on the series' background, including official bios for each alien form used by Ben, providing info about these aliens' species, planets and for some of them cultures, with only a few of them having been actually explored in the various entries. This leaves plenty of material for fans to create their own alien [=OCs=] or develop further the various planets. In addition, Ben is stated to have access to more than one million aliens on the Omnitrix, leaving a huge gap for fans to fill with their own fan-made aliens.
** In ''WesternAnimation/Ben10AlienForce'', the whole Plumber's Kid is based around the idea that a lot of [[HalfHumanHybrid alien-human hybrids]] exist on Earth due to former Plumbers mating with humans. This makes for an excellent justification for fans to create their own half-alien OC.
* ''WesternAnimation/ChipNDaleRescueRangers'' leaves several questions unanswered and thereby FanFic writers with a desire to answer them.
** Monterey Jack is the only Rangers whose parents we get to know. Chip's, Dale's and Zipper's families aren't even hinted at. But in Gadget's case, her father, Geegaw Hackwrench, is mentioned enough to fuel the viewers' curiosity. He is only ever seen in a framed picture in "To the Rescue" Part 3, and Gadget mentions that she has lost him more than one year prior to the events of this episode. What exactly happened to him remains unknown. In a show that has its fair share of mystery and thrillers, this just has to fuel the audience's curiosity.
** Speaking of Geegaw, he and Monty have been in some NoodleIncident in Zanzibar which involved a cheese bread and greatly upset Geegaw. While Monty tells a lot of tales from his past which may or may not be true, this is the one that the Rangerphiles really want to know more about.
** Gadget's mother remains entirely unmentioned. Neither Monty nor Gadget ever talks about her. But if ''CDRR'' fanfic writers have to solve the mystery of Geegaw's demise, it's only natural that they have to write something about her mother as well.
** Then there is "Good Times, Bat Times", the episode in which Dale ends up with Foxglove as his girlfriend. It's often considered the chronologically last episode (there is no defined chronology throughout a show that has the pilot in Season 2). Either way, we don't find out how things go on with Dale in a relationship with a cute pink bat (unless you count [[ComicBook/ChipNDaleRescueRangers the Boom! comics]] as {{Canon}}). Will Foxy join the Rangers? What'll Chip do, now that he doesn't have any competition for Gadget anymore?
** How come there's a mouse in Hawaii that [[{{Doppelganger}} looks pretty much identical to Gadget]]?
* ''WesternAnimation/DannyPhantom'':
** [[FutureMeScaresMe Dark Danny]]'s return, which the show teased at the end of the character's debut episode, but never came into fruition due to the show ended sooner than planned.
** Both creator Butch Hartman, and head writer for the first two seasons Steve Marmel, wanted to do a plot where [[OppositeSexClone Danielle "Dani" Phantom]] would be introduced to Danny's family and adopted, but didn't have time to properly setup such a development. Naturally, fans like exploring this possibility in fan works.
** Fans often wonder what, exactly, happened when Danny first gained his powers, as there's a month between the FreakLabAccident accident and the start of the show; the accident itself is only loosely depicted in the ExpositoryThemeTune and in the episode "Memory Blank" (wherein the characters ''recreate'' it), and we don't see what happened in that first month at ''all''.
** The show in general raises some questions about the nature of ghosts and the Ghost Zone that are never given answers (or [[FanDislikedExplanation ones are just plain unsatisfying]]), leading to fans [[EpilepticTrees come up with their own creative answers for]].
* ''WesternAnimation/{{Daria}}'''s BizarroEpisode, "Depth Takes a Holiday," is often relegated to FanonDiscontinuity, but other times fans wonder: if Lawndale actually has an interdimensional portal, couldn't that set up all sorts of sci-fi/fantasy fics, not to mention crossovers?
* Franchise/DCAnimatedUniverse:
** Many people wondered what happened between the timelines of ''[[WesternAnimation/JusticeLeague Justice League Unlimited]]'' and ''WesternAnimation/BatmanBeyond''. Fifty years had passed and many of the Justice Leaguers are gone. They've also wondered about the circumstances which led to Warhawk, son of Hawkgirl and Green Lantern, being conceived and born.
** Not to mention the "[[NoodleIncident Near-Apocalypse of '09]]".
* ''WesternAnimation/{{Gargoyles}}'' is an absolute treasure trove of this, thanks to [[TooGoodToLast its rather abrupt cancellation]], and [[WhatCouldHaveBeen the creator's extremely detailed notes about the planned future of the mythos]].
** There was going to be a ''Dark Ages'' prequel spinoff focused on the early days of the Wyvern Clan in Medieval Scotland, when Goliath and Demona were still young lovers fighting under Hudson's guidance. Not to mention a planned ''Gargoyles: 2198'' SequelSeries, with the cast's descendants fighting off an alien invasion (first hinted at in "Sentinel") in the far future. Both concepts practically beg for fanfiction.
** The released notes for ''2198'' confirm (among other tidbits) that Elisa and Natsilane's descendants would eventually have gotten together, that Lexington and Xanatos would eventually have merged corporations, and that a line of robots based on Lexington would eventually have entered production. All dynamite ideas for fanfiction.
** After fans pestered him about it in his "Ask Greg" Q&A forum, Creator/GregWeisman confirmed that he did have plans to work characters from [[Creator/WilliamShakespeare Shakespeare]]'s ''Theatre/TheTempest'' into the ''Gargoyles'' mythos. How would they have figured in the story? How would Weisman have portrayed them? How different would they have been from their literary counterparts? Note that the ''Gargoyles'' universe already includes sorcerers, Fae spirits, monstrous humanoids, volatile court politics, and [[DoesThisRemindYouOfAnything an enchanted island fought over by various factions of sorcerers and spirits]]; a retelling of ''The Tempest'' practically writes itself.
** After Demona and Macbeth were made immortal by the same magic spell, they canonically lived through over 900 years of human history--barely any of which has actually been seen in canon. What adventures did they get up to while Goliath and his pals were still sleeping in statue-form?
** [[GreatOffscreenWar The interstellar war between the N'Kai and the Space-Spawn]].
** Alexander Xanatos's time studying magic under Puck's tutelage.
** Alex Xanatos taking up the mantle of Fox from his mother (a possible future plot point that was hinted at in "Future Tense").
** Queen Titania's relationship with Halcyon Renard.
** Peter Maza's relationship with the trickster spirit Coyote (the specific nature of which was left rather vague in-show).
** The careers of Canmore's descendants who took up the mantle of [[LegacyCharacter "The Hunter"]] after him.
** [[WordOfGay Lexington]] acknowledging and coming to terms with his homosexuality.
** The lives and adventures of the gargoyles in the Wyvern Clan [[WeHardlyKnewYe who were all killed off in the pilot episode]] [[DeathByOriginStory shortly after being introduced]], and also those of Angela's rookery brothers and sisters back on Avalon.
** The history and true purpose of the Illuminati.
** The Redemption Squad's battle with the Illuminati after the cancellation of the ''Gargoyles: Bad Guys'' spinoff.
** [[TheLancer Brookyln]]'s adventures traveling through time with the Phoenix Gate (which were going to be the basis of the proposed ''Gargoyles: Timedancer'' spinoff). All we really know from the comics is that his adventures involved [[EyepatchOfPower losing an eye]], traveling to China and Japan, meeting his loyal pet companion Fu-Dog and his true love Katana, and eventually having a son named Nashville (with a second unhatched child nicknamed "Eggwardo" on the way). Whatever he got up to while time-traveling, he apparently had to seriously sharpen his combat skills in order to survive; when he's seen again, he's sporting an armored breastplate and packing a gun, a katana, and a pair of daggers.
* ''WesternAnimation/GravityFalls'':
** Two major examples of this: How the events in the show affected Dipper and Mabel's lives at home after summer vacation ended, and the adventures that [[spoiler:the Stan twins]] got up to after the show's end.
** Stan's ten years on the road after [[spoiler:getting disowned and separated from Ford]] have increasingly become popular, especially for DarkFic and AlternateUniverseFic.
* ''WesternAnimation/HeyArnold'':
** The series was supposed to end with ''The Jungle Movie'', which would have seen Arnold and Helga admit their true feelings for each other, and would have seen Arnold finding his parents, but the show was cancelled and the movie was put on the back-burner. However, creator Creator/CraigBartlett has revealed bits and pieces of the finale's intended plot, and the fanfic community has responded in kind. With Creator/{{Nickelodeon}} producing it as [[WesternAnimation/HeyArnoldTheJungleMovie a TV movie over a decade later]], the fans can now see how similar their takes on the story were to the final film.
** Ditto for Bartlett's unproduced spinoff ''The Patakis'', about the home life of a teenaged Helga. The pilot script was apparently too dark for Creator/{{Nickelodeon}}, but Bartlett has revealed enough details for the fanfic writers to use. Unlike ''The Jungle Movie'', Nickelodeon has not given this the green light yet.
* ''WesternAnimation/InfinityTrain'':
** The train itself. Since it already has the mysterious ability to travel through dimensions, fans like to imagine that humans from the show's Earth aren't the only passengers on the train, and that it can be host to beings (both human and non-human) from various different timelines and dimensions. Cue half of the fics for the fandom consisting of {{crossover}}s with other works.
** The other half are mostly {{Continuation}}s: what is [X]'s life like now that they're off the train? Creator Owen Dennis has stated he had no interest in deeply exploring the lives of characters after they've gotten their exit, which only gives more reason for fanfic authors to do the job themselves and imagine how each season's protagonists are doing now that they're back on Earth and have to deal with not having reflections, being made of metal, or just their lingering emotions about spending weeks/months/years of their lives on the locomotive.
* ''WesternAnimation/InvaderZim'':
** The show contains a surprising amount of background detail upon which numerous fans can and have elaborated, ranging from an interstellar war to Irken reproduction. Especially since the show was canceled just as it was developing a MythArc, and the creators have revealed their basic plans to fans.
** The "Battle Void" StoryArc from the [[ComicBook/InvaderZimOni comic book continuation]] features a series of Zims from {{Alternate Universe}}s, most of them very bizarrely different from Zim himself. This has proven very inspirational ground for fanfic writers, as has the StartOfDarkness for the arc's main antagonist, [[spoiler:Zib, an alternate Dib who defeated his Zim then [[FusionDance merged]] with his PAK]].
* ''WesternAnimation/{{Jellystone}}'': An unorthodox example; fans of the show are fond of redesigning characters from other media, particularly Funny Animal ones, in C.H. Greenblatt's style and calling them the Jellystone versions of them.
* ''WesternAnimation/JimmyTwoShoes'':
** Who is Beezy's mother/Lucius' wife, and what happened to her? There ''was'' a Mrs. Heinous in the early stages of the series' development, but in the final product, she's Lucius' RichBitch girlfriend Jez.
** How did Jimmy and Heloise end up in Miseryville? This was actually addressed in [[WhatCouldHaveBeen the original pitch]] (which was that Jimmy and Heloise died and went to Hell -- by accident in the former's case), but since the final product makes its canonicity dubious, fans have often created their own theories in place, often with elements from the original concept.
* ''WesternAnimation/KimPossible'' has some common jumping-off points:
** Graduation from high school was [[GraduateFromTheStory the ending for the series]] but presumably a new beginning for Kim and Ron. Quite a few fics follow their adventures to college and beyond to adult life.
** A new beginning is also suggested for Dr. Drakken and Shego, who end up [[EnemyMine helping save the world]] instead of menacing it and apparently [[LastMinuteHookup become a couple]].
** The planet Lorwardia was introduced with just enough information to suggest that it's the [[PlanetOfHats homeworld of a]] ProudWarriorRace.
* ''WesternAnimation/TheLoudHouse'' episode "The Loudest Mission" gives us two -- 1) Who's going to buy the Santiago residence? 2) What adventures will Ronnie and Bobby have with their relatives? The latter question was eventually answered by the spinoff series ''WesternAnimation/TheCasagrandes''.
* ''WesternAnimation/TheMagicSchoolBus'' has a pretty devoted fanfic community, largely because of all the tantalizing questions about the characters that it leaves unanswered. Where exactly did [[InexplicablyAwesome Miss Frizzle]] come from, and how did she get her famous bus? What sort of relationship did she have with [[WesternAnimation/TheMagicSchoolBusRidesAgain her sister Fiona]] before she replaced her as teacher? Are there any other teachers at the kids' school, and are they all as... "interesting" as Miss Frizzle? How did the kids handle adolescence and adulthood? And what were things ''really'' like [[CatchPhrase at Phoebe's old school]]?
* ''WesternAnimation/MiraculousLadybug'':
** Are Marinette and Adrien protected (by their miraculouses) against Hawk Moth's powers? If not, their akumatized selves are often represented, and nicknamed White Cat and Miss Fortune, respectively. However, the episode "Zombizou" seems to confirm that they aren't protected against akumatization. Furthermore, the akumatized Chat Noir is canonically named Chat Blanc, which is French for "White Cat".
** Many fanfics have them revealing their secret identities to each other, which has yet to happen in canon, though they have come close a few times.
** [[spoiler:What is the Peacock Miraculous doing in Gabriel Agreste's safe? Fans speculate that either he or his wife used to be the holder, and their costumes are often represented.]]
** In "Chameleon", [[spoiler:Marinette's friends and classmates are quick to force her out of her seat with NoSympathy and are quick to believe that she's picking on Lila when she tries to debunk her lies, leaving Mari to nearly get akumatized twice]]. The episode has lead to a large number of fics that involve Marinette getting ostracized from her class and/or getting akumatized, while the class is no longer trusted by her after they realize [[MyGodWhatHaveIDone what they've done]].
** The American special reveals that there is a Miraculous set based on Native American culture, with Jess gaining the Eagle Miraculous, and WordOfGod revealing the identites of the others. What do the others look like, and who gets them?
* In ''WesternAnimation/ThePenguinsOfMadagascar,'' Rico is animated with a large scar that crosses his beak. It has never been explained in canon, nor do the other characters draw any attention to it, as if they don't even notice it any more. For Rico's past specifically it is a common question of exactly what happened to give him the scar, and how to make it fit in with canon.
* The never-seen biological parents of the title characters on ''WesternAnimation/PhineasAndFerb''. Phineas's mother and Ferb's father are married, [[HappilyAdopted they consider them their parents]], and no mention is ever made of what happened to their biological [[DisappearedDad father]] and [[MissingMom mother]], respectively. This has led to a ''lot'' of fan speculation on the subject.
* ''WesternAnimation/{{Pibby}}'': The very premise of the potential series is that a mysterious glitch starts consuming the worlds of Creator/CartoonNetwork and Creator/HannaBarbera and turning their inhabitants into its blank-eyed rainbow-spewing minions. This makes it easy for fans to come up with their own stories depicting Pibby traveling to places like Creator/{{Nickelodeon}}, the Creator/DisneyChannel, Creator/{{Netflix}}, etc. and have her team up with surviving inhabitants of the worlds depicted in those channels.
* ''WesternAnimation/PJMasks'': Due to the show lacking a proper OriginsEpisode for the heroes and villains, the question of how the PJ Masks became superheroes and how they first met the Night Time Villains has generated multiple fanfics already.
* ''WesternAnimation/{{ReBoot}}'' ended with a satisfactory GrandFinale in the third season, although the seeds of [[GreaterScopeVillain a greater evil in play]] were revealed earlier, the Supervirus Daemon having infected the Guardian Collective (who are normally immune to virus infection). The original air date for the Season 3 finale was 1998, and [[VindicatedByHistory good reruns]] on Creator/CartoonNetwork brought about [[UnCancelled a fourth season]] in 2001 to pick up on the Daemon arc. In the interim, fanfic writers had a field day telling a ''Franchise/StarWars''-esque battle to save the net. When the fourth season finally aired, the story was notably [[HypeBacklash not the epic, sprawling battle expected]] but isolated encounters that took up a whole four episodes to tell. And the less said about ''[[Series/ReBootTheGuardianCode The Guardian Code]]'', the better.
* ''WesternAnimation/RegularShow'' has two: What happened on Earth during the three years the park was in space? And what happened during [[spoiler:the twenty-five years between the park's return and the reunion]]?
* ''WesternAnimation/RoadRovers'' has loads of things for fans to expand on, including the relationship between Parvo and the Groomer, [[SailorEarth adding new Road Rovers or creating their own groups]], and elaborating on the backstories of the Road Rovers.
* ''WesternAnimation/RocketPower'': In the episode "Welcome to [=OttoWorld=]", the Rocket gang burries a time capsule and wonders if anyone will remember them in the future. The episode ends with a scene in which the time capsule is opened again in the distant future, and we get to see four statues of the protagonists. What did they do to apparently get this famous?
* As of Season 5, ''WesternAnimation/SamuraiJack'' has been stuck in the future for 50 years. What adventures did he have during those five decades?
* ''Franchise/ScoobyDoo'':
** The franchise in general, with its simple-but-charming formula, is perfect for any fanfic writer to jump in and play with. Much like ''Series/DoctorWho'', it's ultimately just about a group of close-knit friends and [[WalkingTheEarth their never-ending travels]] in a SignatureTeamTransport, where practically ''anything'' can happen.
** ''WesternAnimation/ScoobyDooMysteryIncorporated'':
*** The original Mystery Incorporated team from the 1960s likely spent ''at least'' as much time solving mysteries as the classic crew, but their adventures are only hinted at in vague flashbacks. Exploring their adventures opens up a great opportunity for putting a darker spin on the classic ''Scooby-Doo'' formula.
*** The show's many cryptic references to past historical mystery-solving organizations who were compelled to hunt down evildoers under the Evil Entity's influence. There were the Hunters of Secrets (a quartet of Mayan warriors with a pet jaguar), the Fraternitas Mysterium (a quartet of Spanish monks with a pet donkey), the Alianza Misterio (a quartet of masked Mexican outlaws with a pet skunk), the Mystery Gang (an all-female quartet of cowgirls with a pet bull), the Benevolent Lodge of Mystery (a secret society of Victorian inventors with a pet orangutan), and the Mystery Fellowship (an eccentric high-society family of detectives living in a dark mansion that ''sank into the Earth'').
* ''WesternAnimation/TheSecretShow'':
** It's revealed in "[[Recap/TheSecretShowS2E12ItsAHamsterWorld It's a Hamster World]]" that Changed Daily and Lucy Woo were the Victor and Anita of their day back when they were agents. Only their final mission together is depicted, though, which begs the question: what must their other missions have been like? Moreover, what kind of rogues gallery did they have besides Hamster Man?
** [[Recap/TheSecretShowS2E5VictorOfTheFuture "Victor of the Future"]] depicts the future versions of Victor (who is now "Changed Pandimensionally" and goes by Jet Strong) and Professor Professor (who is an even bigger {{Jerkass}} than in the present), but not the future versions of Anita, Changed Daily, or anyone else. What are they like?
** [[WhatCouldHaveBeen There were plans for U.Z.Z. to fight another group of aliens called the Puddleheads]], but they were left on the cutting room floor. The Puddleheads were conceived as sworn enemies of the Floaty-heads. What would the Puddleheads look like, and how would they act?
** Surely, U.Z.Z. has more locations around the world than just the U.K. one. Assuming there are indeed more branches of U.Z.Z., what are they like and are their adventures just as crazy as the ones with the U.K. branch?
** What were Victor and Anita's lives like before they met and were recruited by U.Z.Z.?
* As with the various comic books, there is a lot of fandom around ''WesternAnimation/SonicTheHedgehogSatAM'', including possible continuations of the prematurely aborted plot. At least one set of storytellers has gotten their hands on development material from the canceled third season of the series.
* ''WesternAnimation/StarVsTheForcesOfEvil'':
** [[Recap/StarVsTheForcesOfEvilS2E31RunningWithScissors "Running with Scissors"]] is a major source of this. Marco spent sixteen years in a YearInsideHourOutside dimension in this episode, so fans naturally explore the possibilities of all the adventures he must have had during that time. It's also popular to build off of the bittersweet mood of the ending, which implied that Marco would have a hard time readjusting to life on Earth, which [[TheyWastedAPerfectlyGoodPlot ended up not being the case]].
** Another major source is [[Recap/StarVsTheForcesOfEvilS2E32Mathmagic "Mathmagic"]], due to making {{Alternate Universe}}s canonical in the lore and world of ''Star vs.'' and, more importantly, making it canonical that the characters are ''aware'' that there are alternate universes, both of which provided copious amounts of AlternateUniverseFic fuel, especially ones that expanded upon the [=AUs=] already presented in the episode.
* ''WesternAnimation/StevenUniverse'':
** In the episode "Lars of the Stars", Lars and the Off-Colors have gone from forgotten dregs of society hiding from Robonoids in ancient, abandoned areas of Homeworld, to a BadassCrew who hijacked a ship, became SpacePirates and gained an arch-nemesis. What happened in between hiding and escaping from Homeworld, and HOW did they manage those things?
** The episode "A Single Pale Rose" reveals that Pearl has the phone numbers of (at least) nine people. She was shown receiving Mystery Girl's phone number at the end of "Last One Out of Beach City", but it's unclear who the other numbers belong to. Where and how did Pearl get them?
** Gem society and history can also raise various questions, because although the show has plenty of worldbuilding, quite a few things are left to the imagination due to show never straying from Steven's POV and whatever concerns him.
* ''WesternAnimation/TangledTheSeries'' ends with an epilogue rife with this, ranging from how Lance is going to raise Kiera and Catalina to what adventures [[spoiler:Cassandra]] is going to have outside of Corona. Varian also becomes the Royal Alchemist [[WhatCouldHaveBeen and there was an idea for a spin-off show involving him that got scrapped]]. Naturally, there are [[FandomSpecificPlot plenty of fanfics attempting to recreate it]].
* Four words: "The Tournament of Heroines". Fans of ''WesternAnimation/TeenTitans2003'' can only guess how this event at the end of "[[Recap/TeenTitansS2E9WinnerTakeAll Winner Take All]]" turned out, but writers just ''love'' giving their own $0.02 on it. (And ''all'' of them notice that Terra was in the background; how that's handled depends on the writer's personal views of the character.)
* ''WesternAnimation/TotalDrama'':
** The ShowWithinAShow format has naturally led to a plethora of [[FandomSpecificPlot fan seasons]], often populated entirely by [=OCs=]. Not to mention the possibilities for what happens to the canon characters ''after'' the show (or before or between seasons).
** Mike has [[SplitPersonality a disorder]] that basically guarantees he had [[DarkAndTroubledPast a traumatic past]] before joining the show, but this is never elaborated on. The introduction of [[TokenEvilTeammate his evil alter]], Mal, only adds more fanfic fuel to the fire.
* ''Franchise/{{Transformers}}'':
** Many have wondered what happened during the time skip between the last episode of the second season of ''WesternAnimation/TheTransformers'' and ''WesternAnimation/TransformersTheMovie.''
** Since ''WesternAnimation/TransformersAnimated'' left quite a few questions unanswered, plenty of potential there. Especially with the ''[=AllSpark=] Almanac Volume 2'', which contains unused Season 4 material.
*** The same goes for the ''WesternAnimation/TransformersPrime'' finale movie, ''Predacons Rising'' -- namely: Where did [[spoiler:Megatron]] go; did [[spoiler:Starscream]] survive his encounter with the Predacons; how will Team Prime cope after [[spoiler:Prime's death]]; and what became of [[spoiler:Shockwave]]? While ''WesternAnimation/TransformersRobotsInDisguise2015'' answered the [[spoiler:Starscream]] question, it left the others tantalizingly open.
* ''WesternAnimation/YoungJustice2010'' gets quite a lot of this with its large TimeSkip and original [[ScrewedByTheNetwork cancellation-induced]] cliffhanger ending. What did [[spoiler:the Justice League]] do when they were BrainwashedAndCrazy? What happened to [[spoiler:Kid Flash]]? How does [[spoiler:Darkseid]] figure into all of this? That said, the show was UnCanceled, so it could explore these itself.
[[/folder]]

* ''FanficFuel/{{Danganronpa}}''

[[folder:Video Games]]
* ''VideoGame/{{Chrono|Trigger}}'' series:
** Before the release of ''VisualNovel/RadicalDreamers'' and ''VideoGame/ChronoCross'', ''VideoGame/ChronoTrigger'' had many fanfics centering about Magus' search for Schala because Schala's fate is left ambiguous in the end.
** As a sequel to ''Chrono Trigger'', ''VideoGame/ChronoCross'' has a {{Wild Mass Guess|ing}} about [[spoiler:the enigmatic masked magician Guile being Magus searching for Schala (the bonus ending of ''Chrono Trigger DS'' implies Guile being an amnesiac Magus, albeit one from a timeline different from that of the Magus seen in the main storyline)]]. This led to many (though still not very common) novelizations of ''Chrono Cross'' with said {{Wild Mass Guess|ing}}.
** It's worth noting that Guile himself is a FanficMagnet [[spoiler:regardless being Magus or not]], although his fanfics aren't very common.
*** Guile's Japanese name is Alf, which is probably a nod to Janus' cat Alfador. Some fans interpret him as a cat-turned-human.
*** Some fans also prefer having Guile [[spoiler:not being Magus]] by giving him a {{backstory}} which comes from their interpretations. The most common interpretation is Guile being a magician in the past.
*** This is less common, but the interpretations of Guile's comment [[spoiler:(doesn't want the power of darkness because he thinks DarkIsEvil)]] about the Frozen Flame are also prone to be a FanficFuel. This usually comes across as Guile's denial of his identity [[spoiler:as Magus in the past]], but the Frozen Flame is also said to be able to speak not only about the past but also the future.
*** Another less common Fanfic Fuel is about what Guile is hiding behind his DominoMask. Why is the Fortune Teller at Termina shocked when he takes it off?
* In ''VideoGame/{{Cuphead}}'', what the contracts the various bosses made with the Devil granted them (which are only implied in-game) and the events leading up to making those [[DealWithTheDevil deals with the Devil]] has become a fertile source of fan fics.
* The MMO ''Defiance'' and its TV series tie-in has quite an open area for stories set in the world. Including the history detailing between the events of the Votanis Collective arriving at Earth to the end of the show, as well as covering the past events leading up to the Pale Wars, as well as those involved in it and those involved in it. This also opens up for players who continue to play the game to tell stories with their Arkhunter characters and their adventures in the New Frontier. And with the cancellation of the show, it leaves open room for future stories set in the town of Defiance after Nolan and Doc Yewll's departure with the Omec.
* ''VideoGame/DevilMayCry'':
** The ShroudedInMyth nature of [[AscendedDemon Sparda]] is easy fanfiction fodder, particularly as each mainline game adds more and more to his backstory and list of feats without actually showing the particular sequence of events. This only expands further if one takes into account statements made by Creator/HidekiKamiya (either through games he's directed or via Website/{{Twitter}}), particularly the assertation in ''VideoGame/{{Bayonetta}}'' that Sparda's human bride Eva was an Umbra Witch who entered a contract with him -- presumably marking the beginning of [[InterspeciesRomance their courtship]].
** Speaking of ''Bayonetta'', Dante's "Tony Redgrave" alias is, according to Kamiya, taken from Luka's father Antonio as a sign of respect. Coupled with both series featuring an information broker named Enzo, one gets the feeling Kamiya would do a ''DMC''/''Bayonetta'' [[IntercontinuityCrossover crossover]] if he could -- something that fans would very much enjoy considering how popular the idea of Dante and Bayonetta crossing paths ([[UltimateShowdownOfUltimateDestiny and]] [[BackToBackBadasses then]] [[BattleCouple some]]) [[FanonWelding is in fan circles]].
** ''VideoGame/DevilMayCry5'' opened up two big barrels of it. [[spoiler:First, the end of the game has Vergil undergoing a HeelFaceTurn and becoming more of a traditional rival to Dante. As a result, a lot of fics have cropped up that explore this idea, with Vergil adapting to life with the rest of the DMC crew and trying to establish some sort of relationship with his son, Nero. Secondly, after learning that Eva did not, in fact, abandon him and actually died trying to find him and save him, Vergil muses: "That day, if our positions were switched, would our fates be different? Would I have your life, and you mine?" [[ForWantOfANail This has led to quite a bit of fan works exploring that exact premise.]]]]
* ''VideoGame/{{Evolve}}'' takes place on one planet over a relatively short period of time, while additional information revealed creates a much larger universe with the human-monster war lasting years after what we see in the game. Add in the monster's ability to create new breeds opening up the possibility for fan made creations and their extradimensional nature serving as an easy excuse to drop them into any other fictional universe and you have ripe grounds for fanfiction.
* ''VideoGame/{{Fallout}}'':
** ''VideoGame/Fallout4'' takes place ten years after the events of ''VideoGame/Fallout3''. The Eastern Brotherhood of Steel have reverted to a xenophobic and traditionalist ideology, Owyn Lyons has passed away [[spoiler:and so has his daughter Sarah]] and been replaced by [[AscendedExtra Arthur]] [[UsedToBeASweetKid Maxson]], and we have only a few concrete details into the state of the Capital Wasteland except the fact that the Brotherhood have established ''de facto'' rule of the region as feudalistic overlords. This has led to some downright ''juicy'' speculation into events just after the ending of ''3'', the fate or whereabouts of the Lone Wanderer and of other characters, and the current state of affairs in the Capital Wasteland.
** Considering how, as of ''Fallout 4'', all of the canon games (aside from ''Tactics''... [[BroadStrokes kinda]]) have been based on only the West and East Coasts of the former United States -- ''Fallout 1'' takes place in southern California, ''2'' takes place in northern California, ''3'' takes place around Washington D.C. (along with Pittsburgh and Point Lookout National Park), ''New Vegas'' takes place around Las Vegas and Zion National Park, and ''4'' is located around Boston (along with western Massachusetts and Bar Harbor, Maine). Many fans love to come up with theories on what's happened to the rest of the continent. Only a few allusions have been made by the games to what societies exist outside of these two regions (i.e., Ronto, the Erie Stretch, Great Lanta, Crater Banks, and the countless tribes not assimilated by Caesar's Legion or the NCR), so it's mostly been left to fans to decide what ''other'' societies have appeared [[AfterTheEnd in the intervening centuries]].
* Many ''VideoGame/GoldenSun'' fanfics focus on what Isaac's party was up to during the first two thirds of ''[[VideoGame/GoldenSunTheLostAge The Lost Age]]'', before they joined forces with Felix's group.
* ''Franchise/{{Halo}}'':
** All of those Spartans that didn't get a story in either games and or the ExpandedUniverse. Heck, even the ones who are featured in canon are this, since we still only get a tiny glimpse of their adventures.
** The post-war galaxy is this too, since there are hundreds of different factions vying for power in the vacuum caused by the Covenant's collapse.
* In ''VideoGame/HarvestMoonAnimalParade'' there's one marriage candidate called the Witch Princess. She sometimes mentions that she doesn't seem to get along with the Harvest King. If you're married to her, you can hear her say, "If you were to be gone from this world... I wouldn't know what to do. It's frightening. So please don't leave my side." Also, when getting her wish for the Purple Bell, she'll say that she wants a potion or something that will pull the truth out of someone. Has she been betrayed before? Lied to? What if the Harvest King is related to all this?
* ''VideoGame/HenryStickminSeries'': The [[spoiler:"Toppat Civil Warfare"]] ending of ''Mission'' has an infamous cliffhanger. Despite being one of the most hated routes by the fans, due to similar reasons, some may try to continue it, especially after WordOfGod says there will be no sequels or DLC after the finale.
* ''VideoGame/KanColle'', due to the premise being "turn battleships of the Second World War into girls, and be their Admiral" has a '''huge''' cast, is rife with [[HistoricalInJoke Historical In-Jokes]], offers a wide area where stories can take place (most of the Atlantic and Pacific Ocean, as well as coastal bases and cities just about anywhere) and runs the gamut from very comedic to very serious. This allows fan creations of Admirals in all kinds of variations (male or female, old or young, even "Abyssal" Admirals for the enemy faction might exist) as well as battleships without a canon girl equivalent, and fan stories can be almost anything.
* ''Franchise/KingdomHearts'' has a massive MythArc that still contains tons of blank spaces, like the epic [[GreatOffscreenWar Keyblade Wars]], and the mysterious period before the fracturing of the Multiverse. It's also a rare official crossover between dozens of Franchise/{{Disney|AnimatedCanon}} and ''Franchise/FinalFantasy'' works, which leaves plenty of room for exploring how the many established characters fit into the original lore of ''Kingdom Hearts''. [[WesternAnimation/MickeyMouse King Mickey]]'s backstory is particularly juicy: how exactly did he go from [[WesternAnimation/SteamboatWillie a humble steamboat pilot]] to [[WesternAnimation/{{Fantasia}} an apprentice sorcerer]] to a ''[[TheGoodKing king]]'', and how did he meet his chief lieutenants [[WesternAnimation/DonaldDuck Donald]] and WesternAnimation/{{Goofy}}?
* ''Franchise/{{Kirby}}'':
** Kirby's PowerCopying ability technically gives him an unlimited array of potential powers. And with Kirby having abilities that range from martial arts and electricity to ringing bells and parasols, it's quite fun to imagine potential powers for the little guy. And what makes it even more fun is the possibility of them [[AscendedFanon becoming actual powers in an official Kirby game]].
** What would happen if other characters found [[VideoGame/KirbySuperStar NOVA]] [[spoiler:or [[VideoGame/KirbyPlanetRobobot another wish-granting machine]]]], and what wishes would they make?
** What are the [[VideoGame/KirbyAndTheAmazingMirror Mirror World]] versions of characters we haven't seen yet?
** If the [[VideoGame/KirbyPlanetRobobot Robobot Armor]] can take the ability of its wearer, what would happen if someone other than Kirby used it?
* ''VideoGame/TheLegendOfSpyroDawnOfTheDragon'': Very little is explained about Malefor's backstory. Any fanfiction that's not Spyro/Cynder shipping is probably this. His "death" in the final game was also vague, leading to many fanfiction and fan comics.
* ''Franchise/TheLegendOfZelda'':
** Several fics based on ''VideoGame/TheLegendOfZeldaTwilightPrincess'' focus on [[spoiler:what happened to Midna after she returned to Twilight, and if she ever found a way to reunite with Link]].
** For ''VideoGame/TheLegendOfZeldaOcarinaOfTime'', what exactly happened in the seven years that Link was asleep? There's been fan interest in a game where you play as Zelda/Sheik during that time period, and [[https://www.nintendolife.com/news/2021/07/retros_cancelled_zelda_game_starring_sheik_resurfaces_in_nintendo_gigaleak Nintendo had actually planned to make such a spin-off]], but it was scrapped before it saw the light of day.
** Also regarding ''Ocarina of Time'' as well as its sequel ''[[VideoGame/TheLegendOfZeldaMajorasMask Majora's Mask]]'', what did the Hero of Time do upon leaving Termina? ''Literature/HyruleHistoria'' confirms that the Hero's Shade, the ghost who is ''Twilight Princess'' Link's ancestor, is the Hero of Time, so many fanfics dealing with this subject tend to feature how he lost his eye and whom he started a family with (the ranch girl Malon being the most common candidate).
** All the alternate timelines and universes add more of this too. What happened in Termina before and after Link's adventure in ''[[VideoGame/TheLegendOfZeldaMajorasMask Majora's Mask]]'' (and what was Majora's own backstory)? The wars in the past that occurred before ''[[VideoGame/TheLegendOfZeldaOcarinaOfTime Ocarina of Time]]'', ''[[VideoGame/TheLegendOfZeldaALinkToThePast A Link to the Past]]'', ''[[VideoGame/TheLegendOfZeldaSkywardSword Skyward Sword]]'' and various other titles, of which the BigBad is usually one of the last survivors? What happened to so and so character introduced in one game that's never been heard of since? Each of these questions usually starts a lot of ''Zelda'' fan fic...
* ''Franchise/MassEffect'' fans have the two years in which [[spoiler:Shepard is "dead"]] to explore what happened to their old crew, as we only really find out what happened to Garrus and Liara, and even they don't get much detail. The Refusal Ending also counts, since it never shows you what the new species were, how they discovered Liara's message, how they developed as a society and their ultimate defeat of the Reapers.
* While the MMO game ''VideoGame/TheMatrixOnline'' might have been disappointingly short-lived, it did manage to open up a very open-ended continuation of the ''Matrix'' film series, where factions of human warriors loyal to Zion, the Machines and the Merovingian wage a secret war for control of the Matrix in the wake of the Machines' truce with humanity. Many fanfic writers have taken to using this setting as a starting point for {{Continuation Fic}}s exploring the future of [[Franchise/TheMatrix the]] ''[[Franchise/TheMatrix Matrix]]'' [[Franchise/TheMatrix universe]].
* ''Franchise/MegaMan'':
** ''VideoGame/MegaManZero'': [[spoiler:The BigBad is immortal, and Zero's death is left ambiguous.]] Did something else happen to these two after ''[[VideoGame/MegaManZero4 Zero 4]]'' (and before ''VideoGame/MegaManZX'')?
** And for that matter, what about the events that connect the [[VideoGame/MegaManClassic original Mega Man]] to ''[[VideoGame/MegaManX X]]'', and ''X'' to ''Zero''? For the latter, there has yet to be a game covering [[GreatOffscreenWar the Elf Wars]], which is largely mentioned in passing and only briefly showcased in [[AudioAdaptation drama CDs]].
** The First Annual Robot Tournament mentioned in ''VideoGame/MegaMan6'''s opening offers considerable potential for story expansion, both regarding the setup of the tournament itself and the number and diversity of the contestants. How many Robot Masters actually entered the tournament? What were their weapons and weaknesses? Did Cossack enter a robot into the tournament? Were any of the contestants Robot Masters formally introduced in later games? [[note]]The Japanese version sadly eliminates a lot of these possibilities as the First World Robot Tournament was ''beginning'' when Mr. X hijacked the eight contestants. Apparently they were the only eight in the Japanese version. [[TheyWastedAPerfectlyGoodPlot Talk about wasting a perfectly good plot.]][[/note]]
** ''[[VideoGame/MegaManBattleNetwork Battle Network]]'', being an AlternateTimeline to the Classic series where [[ForWantOfANail Dr. Light's research on network technology was funded by the government over Dr. Wily's focus on robotics]], has quite a bit of this going for it.
*** The most common application of the timeline split is [[SailorEarth introducing]] [[AlternateSelf cross-series counterparts]] of characters who'd logically exist in the other course of history. A frequent candidate for [[OCStandIn this]] is [[VideoGame/MegaManBattleNetwork4RedSunAndBlueMoon Dr. Regal]], as [[VideoGame/MegaManBattleNetwork5TeamColonelAndTeamProtoMan the fifth game]] establishes him to be [[spoiler:Dr. Wily's son]]. Surely the [[spoiler:BigBad's direct blood relation]] would be hanging around in the Classic series as well, right? [[spoiler:And considering Regal a) is CardCarryingVillain so repulsive that [[EvenEvilHasStandards his old man]] subjects him to HeelFaceBrainwashing to turn Regal into a productive member of society and b) was driven to [[HumansAreBastards his brand of nihilistc villainy]] after [[BrokenPedestal becoming dillusioned with both Wily and the society that rejected his father]], a number of fans see it fit to hit a Classic Dr. Regal with AdaptationalHeroism instead of portraying him as an OverlordJr or otherwise independent villain.]]
*** Despite some changes [[NonSequiturCausality that are harder to explain]], like [[AdaptationalNationality Dr. Light's nationality changing from American to Electopian]] ([[FantasyCounterpartCulture read: Japanese]]) or the extraterrestrial Duo now being [[VideoGame/MegaManBattleNetwork4RedSunAndBlueMoon an advanced NetNavi who judges intelligent life and destroys the worlds of those deemed wicked]] as opposed to [[VideoGame/MegaMan8 a heroic robot belonging to an intergalactic peacekeeping force]], the fact that [[InSpiteOfANail Wily is still a roboticist]] suggests a lot of backstory details may still be intact between continuities. An interesting (if not overlooked) tidbit comes in ''[=BN5=]'', where it's revealed that the ''BN'' versions of Light and Wily collaborated in their youth on [=SoulNet=] -- [[https://megaman.fandom.com/wiki/SoulNet a concept]] that meshed together their respective fields of study and sounds not too far removed from {{Cyberspace}} as it appears in the ''Zero'' series. One has to wonder if their Classic selves had a similar joint endeavor.
* ''VideoGame/MetalGearSolid'':
** The fandom is particularly fond of writing fics about Liquid's backstory (usually set during his time in the Middle East) or the day The Boss killed The Sorrow. In fact, these two plots are so popular in ''MGS'' fan fiction that almost every male ''MGS'' fan writer has taken on the former, and almost every female ''MGS'' fan writer has taken on the latter.
** Early on in ''VideoGame/{{Metal Gear Solid 2|SonsOfLiberty}}'', Otacon claims that almost every major nation, corporation and political group on Earth ends up developing their own version of Metal Gear in the wake of [[VideoGame/MetalGearSolid Ocelot releasing the weapon's plans]] -- which means that there are likely ''hundreds'' (if not more) models of Metal Gear that we never actually see in the series proper.
* ''VideoGame/Mother3'' leaves most of the details about the TimeSkip after ''VideoGame/{{EarthBound|1994}}'' (''Mother 2'' in Japan) deliberately clouded in mystery and enigma. As such, there are numerous fan works exploring [[spoiler:the catastrophe that completely destroyed the world of ''[=EarthBound=]'']], the people of Tazmily's [[spoiler:journey to the Nowhere Islands after their world's destruction]], and [[spoiler:Porky Minch]]'s [[StartOfDarkness descent into complete evil]], not to mention the full story of [[spoiler:the long-vanished race of people who built Osohe Castle]].
* Let's see, ''VideoGame/{{Neptunia}}''... [[AlternateUniverseFic Multiple dimensions?]] Check. [[ADayInTheLimelight Fleshed out]] [[AlternativeCharacterInterpretation characters]]... Check. Almost no history of its world. Check. [[SelfInsertFic An absolutely moe]], [[MostWritersAreMale all-female cast]]? [[HomoeroticSubtext Heavily implied]] {{yuri|Genre}} [[GirlOnGirlIsHot among said cast]]?! Check-a-doodle-doo.
* ''VideoGame/{{Overwatch}}'' has ''two'' backstories: one of a massive RobotWar that spawned the titular organization, and another of the exploits and controversies of said organization in the years following the war's conclusion. With much of the details being fairly hazy, both with the plot and with the characters' individual backstories, fans have planted a record number of EpilepticTrees despite the game being relatively young.
* ''Franchise/{{Pokemon}}'':
** ''Pokémon'' has generated massive numbers of fanfics over the years, thanks to the sheer cultural presence in the childhoods of an entire generation. The games (especially the early ones) often had sparse characterization and backstories for many characters (including [[HeroicMime the protagonists]]), making {{alternative character interpretation}}s easy for many writers. And we're not even getting into the related media...
** The various "Eeveelutions" are ''fan art'' potential, being far and away artists' most popular subjects. Similar body structures coupled with various elemental themes (and vulpine cuteness) mean they're easy to draw and provide great breadth for creativity.
** Similar to the Eeveelutions potential is the "Regional Forms" introduced in [[VideoGame/PokemonSunAndMoon Generation VII]]. The idea of wildly different regional variants of earlier Pokémon threw open the floodgates to reimaginations of familiar favorites.
* Because Chell in ''VideoGame/{{Portal}}'' has almost no backstory, there is a ''lot'' of room for imagination. Wheatley and [=GLaDOS=]/[[spoiler:Caroline's]] pasts are also very vague, and Chell's future is unknown, as all we ever saw was a cornfield. Since ''Portal'' also ties into ''VideoGame/HalfLife'', there is also potential for crossover stories involved a race between the Combine and Human Resistance to get to whatever Aperture Science tech is on board the Borealis.
* ''VideoGame/PuyoPuyo'':
** Characters besides Klug getting possessed by the demon is a fairly popular subject for fan art. [[https://twitter.com/MZKN002/status/743638925965565952 Possessed Sig]] is a obvious example since [[spoiler:it's implied his miscolored left arm and eye are connected to part of the demon]], but there are plenty others out there, such as [[https://www.pixiv.net/member_illust.php?mode=medium&illust_id=43127812 Possessed Witch]] or [[https://www.deviantart.com/fedoramoron/art/Strange-Tee-796629955 Possessed Tee]].
** Some people enjoy coming up with Mini and Mega forms for characters not present in ''Puyo Puyo 7'', such as Lidelle, Accord or Witch.
** How and why Yu and Rei died? There are hints this was a tragic affair, but it's never further elaborated in the games proper.
* ''VideoGame/{{Pyre}}'': In a certain ending where [[spoiler:Oralech survives and is left on the same side as Volfred, they will rebuild their relationship, but the details of their conversation is left a mystery, leaving any space for romantic or platonic interpretation to their previous relationship]]. The epilogue specifically mentions that they were "seldom seen traveling separate" afterwards.
* There's a three-year gap in the ''Franchise/ResidentEvil'' timeline, between the end of ''[[VideoGame/ResidentEvilCodeVeronica Code: Veronica]]'' and the "Umbrella's End" stage in ''[[VideoGame/ResidentEvilTheUmbrellaChronicles The Umbrella Chronicles]]'', that has never been explored to any serious extent. We've been told here and there that the cast was running around the world fighting viruses, arresting evil scientists, and having adventures, but aside from Leon's adventure in South America in ''[[VideoGame/ResidentEvilTheDarksideChronicles The Darkside Chronicles]]'', it's never really been discussed.
* ''Franchise/SilentHill'', being a premiere MindScrew series told exclusively from the view of the player character ([[spoiler:with the possible exception of ''[[VideoGame/SilentHillShatteredMemories Shattered Memories]]'']]), contains a wealth of information for fans to explore, especially concerning the nature of the eponymous GeniusLoci and the cult that worships it.
* As Creator/SanzaruGames refused to continue the franchise, ''VideoGame/SlyCooperThievesInTime'' had quite a lot of {{Fix Fic}}s that [[spoiler:either justified Penelope's poorly written FaceHeelTurn or undid the DownerEnding, with Bentley and Murray finding Sly in Ancient Egypt and bringing him home, or even having Sly turn up in ''modern day'' Egypt instead]].
* ''VideoGame/SoulSeries'': ''VideoGame/SoulcaliburV'' got barely over a year in development. [[http://train2game-news.co.uk/2012/03/26/train2game-news-soulcalibur-v-story-mode-one-fourth-of-planned-size-each-character-was-to-have-own-story/ The length of its Story Mode was drastically shortened due to time constraints,]] with ''numerous'' plot elements mentioned in official bios prior to the game's release being ignored or glossed over left and right and only a [[NoExportForYou Japanese-only artbook]] attempting to [[AllThereInTheManual fill in the blanks]] of exactly ''what'' happened in [[TimeSkip the seventeen-year interim between]] ''SCIV'' and this game. (Heck, there weren't even character-specific Arcade endings to help shed light on things.) For a while, fanfic writers were scrambling to answer the various questions that ''SCV'' couldn't bother to... only for ''VideoGame/SoulcaliburVI'' [[AlternateContinuity to come along]] [[{{Revision}} and]] [[ContinuityReboot wipe the slate clean]]. Even then, that [[spoiler:''VI'' [[ArcWelding frames the events of its predecessor]] as a definite BadFuture (despite ''V'' ending with both soul swords disappearing into Astral Chaos) and features [[MyFutureSelfAndMe the original timeline's Cassandra tipping off her current-day incarnation to this development]]]] is rife with possibility.
* ''Franchise/SuperMarioBros'': If Princess Peach isn't Bowser Jr.'s mother, then who is?
* As ''VideoGame/SuperSmashBros'' [[NoPlotNoProblem doesn't really do plot]] (barring [[VideoGame/SuperSmashBrosBrawl The Subspace Emissary]] and [[VideoGame/SuperSmashBrosUltimate World of Light]]) it also lacks any sort of real lore. As such, quite a few fans have made their own expansions to the ''Smash Bros.'' world, especially in regards to the OriginalGeneration.
* ''VideoGame/TalesSeries'':
** ''VideoGame/TalesOfSymphonia'' has a two-year gap between the first and [[VideoGame/TalesOfSymphoniaDawnOfTheNewWorld second]] games in the series for fanfic writers to speculate on. Most of the party members also have at least a few gaps to fill in... not to mention the oft-mentioned but barely seen Kharlan War era, four thousand years ago, which has spawned its own subgenre within the fandom.
** Similarly, there's plenty in the post-timeskip epilogue to ''VideoGame/TalesOfTheAbyss'', except that it's more like Essay Fuel since people are just trying to explain [[GainaxEnding what the hell actually happened]].
* ''Franchise/TouhouProject'':
** The lack of backstory for many of the characters or the events of the PC-98 games are prime fanfic (and fan comic and fan video) fuel.
** Yukari's ability to manipulate boundaries is pretty much made for this. What, exactly, constitutes a "boundary"? [[SemanticSuperpower Pretty much whatever the hell she feels like]], allowing stories about going to the moon, de-aging people, hitting people with trains, bringing people from outside to Gensokyo...
* ''VideoGame/{{Undertale}}'' has three burgeoning types of fanfic, coming less than a month after release:
** The Fallen Human's backstory. [[spoiler:Both Chara AND Frisk's.]] The backstory we have is anywhere between vague to nonexistent, so it's fertile ground for fan expansion.
** What happens after the [[spoiler:True Pacifist]] ending. While what we see is incredibly upbeat and happy, that doesn't stop people from exploring just how both human and monster society deals with such a sudden change in dynamic.
** {{Fix Fic}}s regarding the ultimate fate of Flowey[[spoiler:/Asriel]]. Even the best ending seems to give him the shaft, and more than a few people can't help but feel obligated to try and help give even him a happy ending.
** Along with those, what is the fate of the monsters when they [[spoiler:reach the human world]], and how did they get to where they are? There are some things that happen that couldn't have happened within a short time after the game ended ([[spoiler:Toriel teaching at a school being the most obvious]]).
** Who are the [[spoiler:six human souls]], and what is their backstory? Very little is actually given about them in terms of information.
** What if [[spoiler:the skeletons]] switched roles is a popular story. Specifically, what if [[spoiler:you killed Sans first? Would Papyrus become a badass and be the one to give you a hard time]]?
*** While we're at it, [[spoiler:how did Sans get his abilities in the first place? And when (and how) did he become aware of the reset situation]]?
** Who the hell IS [[spoiler:Dr. Gaster]], and what happened to him to cause him (and those who knew him real well) to [[spoiler:not exist anymore]]?
* The ''VideoGame/{{Unreal}}'' series, especially the ''[[VideoGame/UnrealTournament Tournament]]'' games. In the SP games we're given several glimpses of what life on Na Pali used to be before/after the Skaarj invasion, the crash of the ISV-Kran, the landing of the Mercenaries and before the crash of the UMS Vortex Rikers, including [[PlayerCharacter Prisoner 849]]'s vague backstory. We're also left wondering what happened after [[spoiler:Prisoner 849 blows the UMS Bodega Bay]], with either both [[spoiler:the Bodega Bay crew and the Prisoner [[FeaturelessProtagonist itself]]]]. And that's only the first game and its ExpansionPack. In the ''Tournament'' and ''Championship'' games we get vague backstories for every character, location, weapon and vehicle, barring some exceptions. Needless to say, it's part of the reason of why the Unreal series has a really strong GameMod community[[note]]The other being the hugely customizable and powerful UsefulNotes/{{game engine}}s themselves, way before they fueled complete generations of games[[/note]]. With so many ground to cover, odds are that someone already did a campaign for a question you may have.
* How did various yokai in ''VideoGame/YokaiWatch'' become yokai?
* ''VideoGame/YumeNikki'' has little to no context and background information for many areas and characters, including Madotsuki herself, leaves the game's canon very open to fan interpretation and expansion.
[[/folder]]

[[folder:Live-Action TV]]
* ''Series/{{Alphas}}'': Since the team is already established and fighting Red Flag in the pilot (having already met people like Skylar and Marcus), it's interesting to speculate about their unseen earlier adventures.
* Every season of ''Series/AmericanHorrorStory'' thus far has ended with at least one open-ended plot thread left dangling, leaving the door wide open for speculation about what happens after the finals credits roll. And now that WordOfGod confirms that [[TheVerse all seasons take place in the same continuity]] (with Pepper, Sister Mary Eunice and Marcy the Realtor appearing in multiple seasons), the door is also wide open for [[{{Crossover}} characters from different seasons meeting each other]]. Considering the show's vast online fandom, you almost have to wonder if the creators are ''encouraging'' fanfic writers.
** ''[[Series/AmericanHorrorStoryMurderHouse Murder House]]'': What sort of an upbringing did [[spoiler:Michael Langdon]] have, and how did he turn out when he grew up into [[spoiler:the AntiChrist]]? What are [[spoiler:his plans for the world]]?
** ''[[Series/AmericanHorrorStoryAsylum Asylum]]'': What plans did the aliens have for [[spoiler:Kit's two children]]? What happened to Kit after [[spoiler:the aliens abducted him for the last time]]?
** ''[[Series/AmericanHorrorStoryCoven Coven]]'': What sort of adventures did the Salem Witches get up to after [[spoiler:Cordelia became the new Supreme]] and [[spoiler:the student body of Madame Robichaux's multiplied tenfold]]? How did the world react to [[spoiler:Cordelia coming clean about the existence of Witches]]? How did Zoe and Queenie handle [[spoiler:becoming teachers at the Academy]]?
* ''Series/BattlestarGalactica2003'' has the idea of what if the refugee fleet wanders into the territory of space were Earth is a dominant power like [[Franchise/StarTrek the United Federation of Planets]] and find that the Thirteenth Colony is a mighty space power capable of helping them fight the Cylons.
* ''Series/{{Bones}}'':
** The post-Season 5 hiatus (during which time Booth and the Jeffersonian team went their separate ways for nearly a year) has produced quite a few fics. Many of them are also Fix Fics, designed to get Booth and Brennan together, usually [[DieForOurShip eliminating Hannah Burley in the process]].
** The fact that we didn't actually see Booth and Brennan [[TheyDo finally resolve their]] UnresolvedSexualTension in "The Hole in the Heart" has been fodder for more than a few fics. One notable(and lengthy, at nearly 200 chapters and still going) fic, "[[http://www.fanfiction.net/s/7177882/1/The_When_and_the_How_bA_b_bBone_b_to_bPick_b The When And The How: A Bone to Pick]]", suggests that they didn't actually do the deed while she was staying at his apartment after Broadsky killed Vincent, but sometime a few days later, prior to "The Change in the Game", after dealing with Vincent's death and getting some perspective on what they really mean to each other.
** Angela and Hosgins having a second child post finale. Boy or girl? Any more run ins with Angela’s dad over names? How was it different for Hodgins as a parent in a wheelchair?
* ''Series/BreakingBad'':
** How Gustavo Fring built his meth empire, and the beginnings of his vendetta against the Salamanca Cartel.
** Mike Ehrmantraut's time as a cop before he became a PI and got involved with Gus. ''Series/BetterCallSaul'' appears to be focused on showing this as a secondary plot line.
** How Saul Goodman went crooked and built his network of underworld contacts. The producers apparently thought so too, since they decided to actually greenlight a {{prequel}} [[Series/BetterCallSaul spin-off centered on Saul]].
** How the OneSceneWonder [[CorruptCorporateExecutive Peter]] [[TheManBehindTheMan Schuler]] got Madrigal Electromotive involved in the meth trade, and how the alliance between Madrigal and Gus' empire started.
** Events in Walter White's early life that may have triggered his Start of Darkness; his friendship-turned-subtle rivalry with Elliot Schwartz and former romance with Gretchen, his initial involvement with Gray Matter Technologies and maybe how he met Skylar.
** How Jesse became a player in the drug game, his time as a student in Walter's class and getting acquainted with and having misadventures with Badger and Skinny Pete.
** Post-finale:
*** [[spoiler:Jesse's post-Heisenberg life. How will he cope with the resulting psychological trauma from his year in the Aryans' captivity? Will he ever put his life back in order and make an honest living?]]
*** [[spoiler:With "Heisenberg" now one of the most infamous drug lords in American history, what kind of life will his surviving children have? How will Holly White (last seen as an infant) grow up?]]
*** [[spoiler:[[ArsonMurderAndJaywalking Did Huell]] [[MemeticMutation ever leave the safehouse?]]]]
* ''{{Series/CSI}}'': The gap between “immortality” and the ''CSI:Vegas'' revival has some. What led Catherine to step down as supervisor? And everyone else is gone in the start of the revival. We know a little about Grissom and Sara and Hodges from season 1 and Catherine and Lindsey as of season 2, and another character is set to appear, but a lot still remains unrevealed.
* ''Series/DeadMansGun'': The fates of various (usually villainous) characters who take the cursed gun at the end of an episode but no longer have it after the next TimeSkip can be interesting to think about.
* Given that it's a show about TimeTravel, ''Series/DoctorWho'' has ''lots''. Pretty much anything that isn't shown onscreen or in an audiobook/audio drama is game. And sometimes even then!
** The fact that the Doctor can travel anywhere throughout time and space allows for near-limitless {{Crossover}} opportunities with other fandoms.
** The Doctor isn't the only Time Lord renegade, either. How did [[Recap/DoctorWhoS18E5WarriorsGate Romana do freeing the Tharils from slavery?]] What does the Master do when not fighting the Doctor? What about the adventures of [[Recap/DoctorWhoS32E4TheDoctorsWife the Corsair?]] Or [[Recap/DoctorWhoS2E9TheTimeMeddler the Monk?]]
** Various fan attempts of fleshing out companions into more rounded and complex characters than presented in the show; Tegan, Nyssa, Peri, Mel, and other underdeveloped companions get this treatment in fan fiction (and the ExpandedUniverse, for that matter).
** The two years worth of memories that were erased from Jack's memory were never mentioned after his first appearance. So what WERE those memories? And how, and why, were they lost? [[note]]Addressed in ''AudioPlay/BigFinishDoctorWho''.[[/note]]
** There is the alternate universe that was first visited in series two and where Mickey decided to stay to help the effort against the Cybermen; at the end of the series [[spoiler:Rose is trapped there with her family]] and in series four [[spoiler:Human!Doctor and Rose are living there together; a deleted scene showed that they could eventually grow their own TARDIS, though WordOfGod from Steven Moffat denied this idea of the TARDIS]]. What else could the fanfic writers want?
** Rose's time as a Torchwood operative between the events of [[Recap/DoctorWhoS28E13Doomsday "Doomsday"]] and [[Recap/DoctorWhoS30E12TheStolenEarth "The Stolen Earth"]]. We know that she worked for the alternate version of Torchwood in [[AlternateUniverse Pete's World]], but the show never gives any details about what she got up to during her time with them.
** The introduction of the Chameleon Arch in Season 3 opens up some great potential for crossovers, since it means that ''any'' character in ''any'' series could potentially be a Time Lord with temporarily implanted fake memories. Suddenly, all those [[WMG/TimeLord Wild Mass Guesses]] don't seem so stupid.
** Any adventures [[Recap/DoctorWhoS30E6TheDoctorsDaughter Jenny]] may go on to have. [[note]] This is eventually addressed in the comics, when it's explained that she ran out of fuel, worked as a mechanic for more, and kept hopping along until she found an ancient Time Lord time-ship, hopping back to the past to meet the Twelfth Doctor, Eleventh, and Tenth Doctors. [[/note]]
** Though she's certainly a prominent character in-show, the vast majority of River's time-travelling adventures with the Doctor happen offscreen, with many memorable ones only obliquely referenced. Of the fourteen episodes where River plays a central role, in fact, only ''ten'' of them occur at points when they both know each other — leaving plenty of gaps in both of their lives that might actually explain how they grew close enough [[RelationshipUpgrade to consider themselves a married couple]]. Her appearance in [[Recap/DoctorWho2015CSTheHusbandsOfRiverSong "The Husbands of River Song"]] added a ton of new fuel to the fire with the reveal that [[spoiler:their last night together at the Singing Towers of Darillium lasted '''twenty-four years''']]!
** During the Dalek invasion in [[Recap/DoctorWhoS30E12TheStolenEarth "The Stolen Earth"]]/[[Recap/DoctorWhoS30E13JourneysEnd "Journey's End"]], we saw that Sarah Jane, Rose, Jack and Martha helped with the fight. But what about Ian, Barbara, Ben, Polly, Jo, the Brigadier, Tegan and Ace? All of them encountered the Daleks and were presumably still alive and on Earth at the time. Seems hard to believe they would have just been sitting around...
** Donna's [[spoiler:becoming part-Time Lord]] in "Journey's End" has led to some speculation that [[spoiler:she has the ability to regenerate]].
** [[Recap/DoctorWhoS30E15PlanetOfTheDead Lady Christina de Souza's]] past and future capers, especially now that she has a flying bus, could qualify.
** [[Recap/DoctorWhoS31E13TheBigBang Rory's more than 1,800 years guarding the Pandorica]] and [[Recap/DoctorWhoS30E17E18TheEndOfTime The Doctor's time with Queen Elizabeth I]][[note]]later addressed in the 50th-anniversary special[[/note]] are just the tip of the iceberg.
** The two-parter [[Recap/DoctorWhoS32E1TheImpossibleAstronaut "The Impossible Astronaut"]]/[[Recap/DoctorWhoS32E2DayOfTheMoon "Day of the Moon"]] has the three months that [[FiveManBand The Doctor, Amy, Rory, River and Canton Delaware]] spent [[LaResistance fighting the Silence's secret occupation of America]].
** Or for that matter, any adventures [[Recap/DoctorWhoS32E7AGoodManGoesToWar Vastra and the other Jenny]] already had -- and have later with Strax the quirky Sontaran as the Paternoster Gang. The trio are now ExpandedUniverse mainstays.
** Then there is the fact that Clara [[spoiler:was scattered through the Doctor's timestream to save him from the Great Intelligence. She could be written into old or new stories -- or crossovers, such as her cameo in ''Film/CaptainAmericaTheFirstAvenger'']].
** One of the reveals in the Series 9 finale is that the Doctor ultimately spends [[spoiler:four-and-a-half billion years and countless selves]] figuring out and escaping the castle of torture he was imprisoned in, with no company but an ImplacableMan monster who never speaks and kills with a touch. That's a long time to be lonely. How did he pass it?
** After Series 9, Clara and Ashildr, [[spoiler:two women who are essentially immortal, piloting a TARDIS in the shape of an American diner around time and space]].
** Ashildr's many, many unseen adventures taking TheSlowPath from Viking days of yore all the way to [[spoiler:''the end of time itself'', as she outlasts virtually everything else that ever was]]. The ExpandedUniverse jumped on this quick, with a collection of short stories set between [[Recap/DoctorWhoS35E5TheGirlWhoDied "The Girl Who Died"]] and [[Recap/DoctorWhoS35E6TheWomanWhoLived "The Woman Who Lived"]] published shortly after the Series 9 finale aired!
** As of [[Recap/DoctorWhoS36E12TheDoctorFalls "The Doctor Falls"]], Bill's adventures with [[spoiler:Heather]].
** [[Recap/DoctorWhoS38E1E2Spyfall "Spyfall"]]: [[spoiler:The Master]] is forced to spend 77 years on TheSlowPath after getting stranded in 1943, and implies he spent a great deal of that time ''escaping'' from various locations, implicitly including a few prison breaks. What was he doing?
** ''Series/{{Torchwood}}'' establishes that Jack has been working for Torchwood for a century. That's ''loads'' of adventures. Then there's all the, ahem, ''adventures'' he had with various men and women. And aliens. Plus, since the series ended on a cliffhanger, what happened to [[spoiler: Rex]] after he resurrected at the end of ''Series/TorchwoodMiracleDay''?
** ''Series/TheSarahJaneAdventures'' also ended partway through its fifth series, due to the tragic passing of the lead actor. What did Sarah Jane do before she met the kids? Who did they help or fight between stories? What happened afterwards? Did Sarah Jane die at around the same time as her actress?[[note]][[CharacterOutlivesActor Canonically, no.]][[/note]] What did her gang do after leaving Bannerman Road? Did Clyde and Rani ever hook up?
* ''Series/ColdCase'': The compelling natures of most of the victims' stories and the happy ImagineSpot or alternate universe in "Bad Night" make it interesting to imagine the events leading up to the the murders in other episodes being avoided due to ForWantOfANail plot deviations.
* ''Series/TheGoodPlace'': [[spoiler:Michael restarted the neighborhood over 800 times, including one that lasted 11 months. Only a handful of moments from a handful of these restarts are seen onscreen.]]
* ''Series/HoratioHornblower'':
** What exactly has Jack Simpson been doing to Archie and other midshipmen? Clayton's line ("You don't know ''half'' what he's capable of") implies horrible things. Archie is particularly scared by him and his presence gives him seizures. His ominous "Jack's missed you, boy" implies sexual abuse.
** How come Archie knew Drury Lane like it was his home? Was he an avid theatregoer? Was he a teenage actor? To what extent did he know Kitty Cobham? Usually involves lots of love for The Bard, because Archie was fond of Shakespeare and quoted him, both sober and delirious.
** What happens between Archie and Horatio in the Spanish prison when they return and they share the cell like before, but ''sans'' surly Hunter?
* ''Series/HouseOfAnubis'': Fabian's the only character whose parents had never even gotten a single mention during the course of the series. Naturally, fans are interested in exploring his missing backstory, often trying to come up with a reason why he never mentioned his parents.
* ''Series/ICarly'':
** Everyone's parents. Out of the six parents of the main trio (and Spencer, who is Carly's brother), only one was shown (Freddie's mom Mrs. Benson), one was [[NoodleIncident referred to]] (Sam's mom) until she showed up in a single episode, Spencer and Carly's dad is in the military and rarely shows up in one-sided phone conversations. This leaves Sam's father, Freddie's father and Carly/Spencer's mother, and they have never even been mentioned.
** Why did Freddie end up in Seattle, or more accurately, why did his mother come to Seattle on her own, with him. Often combined with the father question.
** Since the revival of the show, Sam Puckett's now a part of a biker gang dubbed the Obliterators. Curious as to how her adventures with the gang would turn out?
* It's easy to wonder about all the possibilities for adventure surrounding the concept of the Red Pirates in ''Series/KaizokuSentaiGokaiger'', as they traveled the universe gathering the Ranger Keys.
** What does Claire find after sailing to Europe (the show has a post-apocalyptic setting) in "To Sail Beyond the Stars"?
** Why are there no children in the Valhalla Sector in the "Letters from the Other Side" two-parter? And if they are there, out of sight, what happens to them [[spoiler:after Meghan wipes out the adults there]]?
** How a lot of the communities (even well-equipped ones like Thunder Mountain) shown in the show, despotic and peaceful alike, made it through the initial years after the death of adults is interesting to imagine. There are also a lot of blanks to fill in about how the leaders of so many settlements (like Millhaven and the village from [[spoiler:"The Touch"]] fell under the Valhalla Sector's influence.
* ''Series/LegendsOfTomorrow'':
** An example similar one to ''Series/{{Buffy|TheVampireSlayer}}'' below; how did Season 3 and Season 4 go with [[spoiler:[[BackstoryInvader Behrad]] instead of Zari]]?
** In a smaller example, since Leonard Snart's brief mention of the name "Alexa" while recalling a robbery that went wrong in Season 1, a few interpretations of the mysterious Alexa have appeared in fanfic, usually in the form of a female criminal who screwed Leonard and Mick over.
* A surprising number of ''Series/LoisAndClark'' fics were inspired by the episode "That Old Gang of Mine", specifically one scene where Clark is shot at point blank range by a mobster's bullet. More than a few stories tried to explain how Superman dealt with the possibility that he might never become Clark Kent again, since the rest of the world thought Clark had been killed.
* The alternate universe on ''Series/TheMiddleman''. What happens with Fatboy Industries? Do alt!Middleman and alt!Lacey save the world? And what does aerosolized soup taste like, anyway?
* ''Series/TheLordOfTheRingsTheRingsOfPower'': Only days after the airing of Season 1, Episode 8, fan fiction portraying [[spoiler:Galadriel saying yes to Sauron's proposal]] appeared.
* ''Series/{{NCIS}}'': Season gaps tend to inspire this on NCIS. How did Tony hold the team together after Gibbs quit? How did Gibbs adjust to his temporary team? How did Ziva survive Somalia? Look up "NCIS" and "Somalia" on fanfiction.net, and you get over two hundred results.
* ''Series/NoOrdinaryFamily'': The cliffhanger ending of the series can inspire a lot of fan fiction, given how the eponymous family is recruited by the government to pursue a plane load of convicts who just got permanent superpowers. George apparently getting powers, Joshua and Katie giving birth to a super-powered baby, and the Powell family being in a position to expose Burton to the government adds to the fan fiction potential.
* ''Series/Numb3rs'':
** There are many fan fics set in Don and Charlie's childhood, which explores what it was like for them both to grow up with Charlie being a math genius.
** Similarly, what Don was doing during his time in fugitive recovery.
** There are some fan fics inspired by certain episodes like, "Uncertainty Principle", "Janus List", among others.
** What life is like for the characters after the series ended.
* ''Series/PersonOfInterest'':
** The final season of revealed that the Machine had started recruiting more operatives so that it could help the Irrelevants in places other than New York. This leaves things wide open for crossover stories where characters from other stories are recruited to be the Finch and/or Reese of their neighborhood.
** The penultimate episode has another one. The Machine presents Finch with an alternative universe in which it was never created. [[spoiler:It involves both Root and Shaw serving Samaritan instead of The Machine, leaving room for them to become a couple again.]]
* ''Franchise/PowerRangers'':
** There's the golden question of what former Rangers do once their show ends -- do they just retire peacefully or do they fight other enemies elsewhere in the world? The [[ComicBook/MightyMorphinPowerRangersBoomStudios Boom Studios comic]] did an entire mini-series using this premise, showing Kimberly, Zack, and Trini fighting Goldar and a new enemy in the background of events during Season 3. Additionally, the page quote comes from an interview where Creator/JohnnyYongBosch says he subscribes to a similar theory for his character Adam, disregarding the throwaway line about him running a dojo in the MilestoneCelebration episode [[Series/PowerRangersOperationOverdrive "Once a Ranger"]].
** What kind of adventures did ExperiencedProtagonist Taylor and her gradually growing group of companions have (outside of the flashback episodes) in the year before Cole joined the ''Series/PowerRangersWildForce'' team?
** In ''Series/PowerRangersMysticForce'', the previous war against The Master and his forces is only featured in a few short flashbacks but can invite a lot of speculation about what Udonna, her sister, Leanbow and his fellow Mystic Wizards, Jenji, Daggeron, and their friends were up to.
* ''Series/{{Smallville}}'':
** The summers between the high school years in the early seasons. The dominant one is the (in)famous "red K summer" between season two and three, which involves Clark on red kryptonite, which stripped his inhibitions and turned him into an amoral party animal, while Chloe visited him and tried to get him home. You could probably guess [[CoitusEnsues how half of those fics ended...]]
** Then of course, being the origin story of Superman, there are loads and loads of fics that tells the tale of the Man of Tomorrow (literally) in the Smallville universe.
** And then, there is the pre-series times, which has quite a few {{Noodle Incident}}s mentioned in the show. The first meeting of [[FanPreferredCouple Chloe and Clark]] is also frequently used, although [[spoiler:their FirstKiss was shown in Season 8]].
** And in Season 9, after [[spoiler:Chloe and Oliver]] are StrangledByTheRedString, [[AbandonShipping abandon shippers]] from other factions filled the empty space where the build-up belong.
* ''Series/StargateSG1'':
** The Season 1 episode "Tin Man" is probably this. After all, the episode ended with android versions of Jack O'Neill and Samantha Carter (plus the others...) roaming around. And the boys didn't realise that they weren't fully human until Doc Fraiser tried to take a blood sample... So everything must be there. I shudder to think of how many fanfics out there have them realising that the military regulations that keep the real Jack and Sam apart no longer apply to the android versions...
** Then there's the episode where a rogue Asgard made a teenaged clone of Jack. The clone survived the episode and went off to live his own life. There's all kinds of trouble a kid with the memories and skills of a special-forces veteran can get into.
* ''Franchise/StarTrek'', with its vast, expansive [[Franchise/TrekVerse universe]] of characters, time traveling, [[AlternateTimeline alternate realities]] and {{Crossover}} potential, never seems to run out of material.
** Before the release of ''Film/StarTrekGenerations'', countless fanfics had abounded centering on the meeting between Captains Kirk and Picard.
*** [[spoiler:And, of course, the various stories of Kirk's resurrection by enraged fans after they DroppedABridgeOnHim in ''Generations''. Notably, [[Literature/StarTrekShatnerverse Shatner himself got involved in that]].]]
** Similarly, Tasha Yar being KilledOffForReal so early has inspired a number of alternate-universe fics exploring a reality where she didn't die in the first year of the ''Enterprise'''s mission.
** The early life and reign of Khan Noonien Singh during the Eugenics Wars.
*** Also stories of the time during which he and his followers were marooned on Ceti Alpha V.
** Events prior to, during, and after World War III.
** What the Earth probe ''Voyager 6'' went through to achieve consciousness [[spoiler:[[Film/StarTrektheMotionPicture and become V'ger]]]].
** The histories and beginnings of several enigmatic ''Trek'' species such as the Talosians, the Borg, the Xindi and, especially, the Q Continuum.
*** What pre-logic Vulcan life was like and what exactly led to the Romulans and Vulcans splitting during the Age of Surak.
*** The origin of the Guardian of Forever.
** The century-length gaps between the shows such as that between the [[spoiler:founding of the [[TheFederation United Federation of Planets]]]] seen in ''Series/StarTrekEnterprise'' and the events of ''Series/StarTrekTheOriginalSeries''.
** What any of the post-TOS characters (i.e.; ''[[Series/StarTrekTheNextGeneration Next Generation]]'', ''[[Series/StarTrekDeepSpaceNine Deep Space Nine]]'', ''[[Series/StarTrekVoyager Voyager]]'', ''[[WesternAnimation/StarTrekLowerDecks Lower Decks]]'', and ''[[Series/StarTrekPicard Picard]]'') are like in the [[Film/StarTrek2009 Kelvin Timeline]].
** The formative years of core characters from each of the shows.
** Notably, we've only seen brief glimpses of the full adventures of the crews of the USS ''[[LegacyCharacter Enterprise]]''-B and the USS ''Enterprise''-C (in ''Film/StarTrekGenerations'' and the ''Series/StarTrekTheNextGeneration'' episode "Yesterday's Enterprise", respectively), fueling some speculation about how they carried on Kirk's legacy.
*** Even the ''Enterprise'' herself, specifically her design, inspiration and construction has gotten backstories.
** Let's also not forget the MirrorUniverse.
--->'''Jim Wright:''' I'm sure this opening shot alone sparked a dozen fanfics. Many of which included the words "Yes, Mistress."
* ''Series/{{Supernatural}}'':
** The show gives fans Dean and Sam's entire childhood to deal, Sam's "Stanford Era" is popular, though it doesn't necessarily focus on Sam. The rest of their childhood leaves plenty of questions. Just how much ParentalNeglect did the boys actually suffer? How many schools did they go to? What caused the rift between Bobby and John? The list goes on.
** There are also the multiple [[AlternateRealityEpisode alternate realities]] established/suggested: "What Is and What Should Never Be" (2x20), [[ItsAWonderfulPlot "It's A Terrible Life"]] (4x17), [[BadFuture "The End"]] (5x04), and [[AlternateHistory "My Heart Will Go On"]] (6x17).
** Also, the four months Dean was in hell (or the whole [[YearInsideHourOutside forty years]], depending on the brother the fic focuses on).
** Dean, Castiel, and Benny's time in Purgatory features in a lot of fics since they were there for at least a year but only moments were featured onscreen.
** The season finales have a tendency to leave a few questions unanswered, which has authors try to explain what will happen before the next season premieres. There are also frequent {{time skip}}s between seasons, which work for this.
** The highly polarizing series finale leaves several avenues open, [[spoiler:especially the tacked on post-Destiel-is canon-and-then-BuryYourGays line that states that Castiel has been freed from The Empty and is helping Jack rebuild Heaven, plus the fact that Dean is also in Heaven. Additionally, because we never see who Sam marries, many fic writers have decided he married Eileen, one of the few female love interests that the fans didn't automatically hate.]]
* In ''Series/TerminatorTheSarahConnorChronicles'', mainly the relationship between John and Cameron. Many fans have waited for The Big Damn Kiss between Cameron and John. Unfortunately, it never happened.
* Similar to ''Series/ICarly'', there's the parents of characters from sister show ''Series/{{Victorious}}''. Only Tori and Trina's parents are seen regularly, Jade's dad was mentioned on one occasion, and both Beck's parent's appeared off screen in on episode. Often fics that mention the parents will have Andre's parents dead, Jade's parents either abusive (especially if it's an angsty fic) or just neglectful and uncaring, the latter being more supported by canon. Cat's parents are generally pretty neglectful as well, though just ''how'' neglectful they are depends on the fic. Robbie, being the ChewToy and TheWoobie will almost never, ''ever'', have a happy home life, and as of "Locked Up'' that view is pretty supported by canon. Beck's usually the only one who will have anything close to good parents, although there will usually be a few issues considering that he lives in an RV just so he can get away from them.
* [[Creator/JossWhedon The Whedon Verse]] have seen a ''lot'' of these:
** ''Series/BuffyTheVampireSlayer'':
*** Wish!Verse: Remember that AlternateUniverse from "[[Recap/BuffyTheVampireSlayerS3E9TheWish The Wish]]" where Buffy never came to Sunnydale? How did Xander get turned? How did Willow? What happened with Darla? How did Angel became a wreck?
*** Insert!Dawn-Fic: Everyone in the Cast was given false memories of Buffy's little sister Dawn in the Fifth season. How would any given episode in the first four seasons play out with Dawn there? In universe certain sources RetCon Dawn into the storyline, the AnimatedAdaptation intended to do this and one of the season eight comics has Buffy dream of season one with Dawn.
*** Normal!Verse: "[[Recap/BuffyTheVampireSlayerS6E17NormalAgain Normal Again]]" told us that the entire show was a hallucination being created by Buffy in an insane asylum. Describe that world. Maybe the {{Big Bad}}s are all just manifestations of her doctors.
*** Yet Another Halloween Fic: Also called YAHF for short, these deal with "[[Recap/BuffyTheVampireSlayerS2E6Halloween Halloween]]" where people wearing cursed Halloween costumes started turning into the things they dressed as. ''Fanfic/HalloweenWorld'' is probably the most famous among the fandom.
*** Hell, Halloween Fics have sprouted a tiny subgenre: Xander gets all the abilities and hardware (including a certain blue A.I.) of [[Franchise/{{Halo}} Spartan-117]].
*** "[[Recap/BuffyTheVampireSlayerS3E18Earshot Earshot]]" has spawned several fics regarding [[CovertPervert Willow's]] comment about...ahem, [[GenderBender her idea]] of the aspect of the demon.
*** The episode "[[Recap/BuffyTheVampireSlayerS3E12Helpless Helpless]]" dealt with Buffy losing her slayer powers due to a ritual. What if she never got her powers back? Would she still fight monsters or use this chance to live a normal life?
*** Buffy is only the latest in a long, long line of women who slay monsters. In one short story, describe one of these previous -- or future -- Slayers.
*** What were the Trio up to during "[[Recap/BuffyTheVampireSlayerS6E7OnceMoreWithFeeling Once More, With Feeling]]" and what was their song like?
** ''Series/{{Angel}}'':
*** Connor!Be-Gone-Fic: Angel DealWithTheDevil-ed his son into a happy family and removed all memories of his son from his crew. How did this affect their recollection of seasons three and four? How did Wesley get that scar? Also obvious fodder for [[ShipsThatPassInTheNight Connor/Dawn]] angst-fics.
** ''Series/{{Firefly}}'': Anything, really.
*** How Wash and Zoe fell in love. Wash’s tribute comic doesn’t even really show a lot aside from the honeymoon.
*** Simon's time studying as a doctor.
*** What Book did before he was a shepherd. This was finally given canon information in ''The Shepherd’s Tale'' comic.
*** Heck, let's just say everyone's backstory. We get the Book comic, a little on Wash, a bit on Jayne in comics and books, and a snippet on something with Inara in the comics but that’s about it.
*** What was the first time Patience shot Mal?
*** The War of Independence
*** And probably the biggest one post-''{{Film/Serenity}}'': Where does the ship go next after Miranda? This was eventually addressed somewhat in the comics though not without more fuel being added in the process (see the comic book entry)
* ''Series/TheXFiles'':
** By its nature of not showing much of Mulder and Scully's personal lives on screen, the show generates quite a bit of fuel. There are many, many fics about just how Mulder and Scully got from the end scene of "all things" to the opening shot of the same episode; it's heavily implied they slept together, but doesn't show anything else.
** Just what Mulder and Scully did between the end of the series and the second movie (''Film/TheXFilesIWantToBelieve'') is also explored quite a bit in fanfiction.
** The fate of Scully's son William whom she put up for adoption. Many, many fans disliked it and thought his adoptive parents could not protect him from the conspiracy. The fics are about Mulder and Scully searching for him or describing his life.
[[/folder]]

[[folder:Film — Live-Action]]
* ''Film/Carrie2002'': In the film's new ending, [[spoiler:Carrie]] survives the prom and moves to Florida. This was meant as a setup for a TV series that was never made; what adventures would she have had there?
* ''Film/TheDarkCrystal:''
** The [=urSkek=]--the race that was split into the [=urRu=] and the Skeksis--are canonically ''not'' native to the planet of Thra, but arrived there after being banished from an entirely different world. Where did they come from? What was their world like? And what kinds of adventures did they have there?
** Mother Aughra is canonically [[Really700YearsOld one of the oldest beings in Thra]], and has witnessed most of the important events in the planet's long history. What kind of adventures did she have in her younger days?
** Even before ''Series/TheDarkCrystalAgeOfResistance'' came out, there were tons of fanfics speculating about what Thra was like before the Skeksis seized the Crystal, and what Gelfling society was like before the Skeksis wiped them out.
* Happens a '''''lot''''' with ''Film/TheDarkKnightTrilogy'' fanfics featuring how ComicBook/TheJoker got those scars of his, simply because he was [[UnreliableNarrator so inconsistent about them]] in the film.
** The third film, ''Film/TheDarkKnightRises'', seems to practically be powered by fanfic fuel. First off, it's the TimeSkip -- the film takes place eight years after ''Film/TheDarkKnight'', hence a gap for fanfic writers to have a stab at. Then, there are all the backstories of the characters introduced in the film. Bane's background and how he got excommunicated from the League of Shadows. Wayne Enterprises board member Miranda Tate, how she rose up the ranks and [[spoiler:her relationship with her father, Ra's al Ghul]], and the slightly shippy nature of her relationship with [[spoiler:Bane]]. GCPD Officer John Blake - his growing up in the orphanage, his police training and, once the film ends, [[spoiler:how he takes on the mantle of Batman as a Batman-Robin-Nightwing hybrid]]. And of course, Selina Kyle. Her past, how she met her roommate Jen, her misadventures as a younger girl and [[spoiler:all the little Bat-Cat babies she and Bruce would have, since the film ends with them together.]]
** To say nothing of the fact that everyone in ''Rises'' seems to go out of their way to pretend ComicBook/TheJoker [[ChuckCunninghamSyndrome never even existed]].
** And specifically related to ''Film/BatmanBegins'': the League of Shadows' involvement in world history, in light of Ducard's claim that they were responsible for the Fall of Rome, the Black Plague and the Great London Fire. For that matter, there's [[spoiler:the careers of the men who previously held the title of "Ra's al-Ghul"]].
* ''Film/{{Inception}}'':
** The movie's famously ambiguous ending, which [[spoiler:suggests that Cobb may have stayed in the Dreamworld after his big heist]], practically begs for a ContinuationFic.
** The details behind the history of [[AppliedPhlebotinum dream-sharing technology]] are left very vague, beyond a brief mention of it being developed by the military for training simulations. And since the existence of the technology is apparently [[TheMasquerade kept hidden from most people]], it makes one wonder what kind of unsavory stuff the government has used it for in the past.
** Related: how did thieves like Cobb and his crew first get their hands on dream-sharing technology?
** Even if you believe that Cobb retires from crime by the end of the movie, what will other dream-thieves do once word gets out that inception (read: '''undetectable brainwashing''') is possible? What's to stop them from using it on world leaders? What's to stop world leaders from using it on terrorists and political dissidents? If one inception job could stop an industrialist from monopolizing the world's energy supply, how will inception affect the world's political landscape?
* ''Franchise/IndianaJones'':
** ''Film/IndianaJonesAndTheKingdomOfTheCrystalSkull'' establishes that Indy was an active OSS agent throughout the whole of UsefulNotes/WorldWarII, opening up six years' worth of high-stakes adventures fighting the Nazis in the middle of an all-out shooting war (the original trilogy took place in the years just prior to the war). And that's not counting the ten-odd years that he spent spying against the Russians with the CIA between the events of ''Last Crusade'' and ''Crystal Skull''.
** Also, there's the famous ending of the original ''Film/RaidersOfTheLostArk'', which heavily implies that the US government has a secret warehouse of mystical artifacts that [[HeroOfAnotherStory other G-men like Indy]] acquired in previous secret missions. What artifacts are the government hiding? How did they obtain them? What are they planning to do with them?
* ''Film/IngloriousBasterds'': How did Aldo get his scar?
* ''Film/JurassicWorld'' has both pre and post-canon examples:
** Pre-canon: How did the titular park become a reality? What happened to Isla Sorna? How did they manage to recapture Rexy? Why did Hammond change his mind about the park? What is Simon Masrani's connection to him?
** Post-canon: [[spoiler:Blue, Rexy, a flock of pterosaurs and who knows however many prehistoric creatures have been left to roam free all over Isla Nublar. What are they getting into now? How is Blue doing after losing her pack? Are she and Rexy working together to survive? Will the ''Mosasaurus'' live or will she starve without anyone to feed her?]]
* ''Film/{{Labyrinth}}'' fanfics speculating on [[Music/DavidBowie Jareth's]] backstory are common, in part because even the AllThereInTheManual material had little to say on the issue. How exactly did a handsome RealityWarper who looks, for all intents and purposes, human wind up as the ruler of a land of UglyCute baby-stealing goblins who turn their captives into more of their kind?
* Franchise/MarvelCinematicUniverse:
** Following the events of ''Film/CaptainAmericaTheWinterSoldier'', the titular Winter Soldier [[spoiler:flees in search of a way to move on with his life or reclaim his lost memories]]. So, what all did he get up to, and what was it like for him to [[spoiler:adjust to civilian life]]?
** The ending of ''Film/AvengersInfinityWar'' managed to become fanfic fuel for ''other'' fandoms -- to wit, the fan author takes a list of relevant characters, [[spoiler:flips coins to see who does and doesn't live through The Snap]], and deals with the aftermath from there.
** The ending of ''Film/AvengersEndgame'' opens up multiple storytelling possibilities, which may or may not be explored in future movies:
*** Tony Stark now [[spoiler: has a daughter named Morgan, who could be in any number of {{Future Fic}}s.]]
*** Steve Rogers now [[spoiler:spent about 50 years HappilyMarried to Peggy Carter]], but ''also'' apparently [[spoiler:got a new shield to replace the one that Thanos destroyed]]. So, [[spoiler:what ''else'' did he get up to during those 50 years]]?
*** Hawkeye [[spoiler:spent five years as a lethal vigilante]] after [[spoiler: his wife and children got snapped away]]. During that time, he apparently [[spoiler:battled Mexican drug cartels and Japanese yakuza gangs, among other things]]. What ''else'' has he been up to?
*** During the events of that movie, Steve Rogers [[spoiler:goes back in time to steal Loki's scepter]]. While he's there, he cons [[spoiler:the scepter]] out of the wrong hands by ''claiming to be HYDRA'', then gets into a fistfight with [[spoiler:his past self]] and tricks his way out of that by telling him that [[spoiler:Bucky's alive]], and then gets the hell out of there. So, with all that in mind, what happens next?
** Pick any fic with Peter Parker as the focus. One of the following scenarios will likely be explored:
*** Aunt May's subsequent reaction to the end of ''Homecoming'' when she discovers Peter's identity, and how Peter convinces her to let him continue.
*** Aunt May gets a bridge dropped on her solely so that Tony can swoop in and adopt the boy as a son, sometimes with Pepper as his new mother. Occasionally, a different Avenger becomes Peter's primary caretaker before Tony comes into the picture, or several Avengers (sometimes in a ''Civil War''-noncompliant arrangement or not; Bucky Barnes optional) become his new family, but it's usually just Tony.
*** Tony elevating Peter's "internship" to an actual one, allowing him to work alongside him on various projects.
*** An explanation of the exact circumstances of Peter getting his powers, usually involving Oscorp.
*** The Avengers reuniting after Civil War, and their reaction to the knowledge that Tony had drafted a kid in the battles. Expect such nuances as Black Widow calling Peter "Little Spider", Cap freaking out at his having dropped an airport bridge on Peter, and them deciding to train Peter better since he won't stop being Spiderman.
** Peter's class taking a field trip to Avengers Tower/Facility, and their reactions, (especially Flash's), reaction to finding out that Peter does know Tony Stark and the Avengers. For bonus points and hilarity, Peter's identity may be revealed to them.
* The ''Film/ANightmareOnElmStreet2010'' remake briefly suggested at a PlotTwist where Freddy Kruger was actually innocent of the crimes he'd been killed for -- this turned out to be nothing more than a RedHerring, but nevertheless, the fanfic writers took to it like a fish to water...
* ''Film/RedEye'' is a standalone film, but it has a pretty devoted following full of fanfic writers. Common plots include Jackson Rippner's past, as well as who his employers are, and most especially the {{Continuation Fic}}s exploring where the story could go after the events of the movie.
* ''Franchise/StarTrek'':
** The alternate timeline started by ''Film/StarTrek2009'' blows the doors wide open for stories exploring the new lives of the main characters, the altered history of the Federation and Starfleet, the new balance of power between the Federation, the Klingons, and the Romulans (Starfleet having bigger, faster ships thanks to scans of the Narada, the Romulan/Vulcan connection being known early, etc.)
** ''Film/StarTrekBeyond'': The USS Franklin was lost long before the timeline was altered, so there should be a Prime universe version of Krall out there.
* ''Franchise/StarWars'':
** Long before the prequel trilogy was released, there were fanfics about the rise of the Empire and Anakin Skywalker's turn to the Dark Side.
** Not to mention events that happened ''longer'' before the prequel trilogy, such as the founding of the Republic and of the Sith Order.
** There are also a ton of Luke and Darth Vader stories. Luke/Vader stories are among the most popular nonromantic stories in fan-fiction history.
** Now that the release of ''Film/TheForceAwakens'' has led to every previous ExpandedUniverse work (with the exception of ''WesternAnimation/StarWarsTheCloneWars'' and its spinoffs) being ExiledFromContinuity, the 30-year gap between ''Film/ReturnOfTheJedi'' and the Sequel Trilogy (along with pretty much everything before the Prequel Trilogy) is a giant blank slate, and this is fertile ground for fanfics.
** Speaking of, the gap between the prequels and the original trilogy has been popular since ''Revenge of the Sith.'' Especially since that movie teases other Jedi surviving the orginal Order 66 purge.
** The year between ''Film/TheLastJedi'' and ''Film/TheRiseOfSkywalker'' is also a relatively undetailed period of time, making it a goldmine of fanfic content, between Kylo Ren's reign as the First Order's Supreme Leader, Rey's continued Jedi training under Leia, and Palpatine preparing his Final Order.
** Speaking of the ExpandedUniverse: since the sprawling ''Franchise/StarWarsLegends'' saga is now effectively cancelled, and may never get any new material following the adventures of Ben, Jaina, Jag, Corran, Kyp, Allana, and the rest of the gang, it's now open season for finally concluding their stories and wrapping up the last few dangling plot threads. In particular: there's the 85-year gap between ''Literature/StarWarsCrucible'' and ''ComicBook/StarWarsLegacy'' that covers Luke PassingTheTorch to a new leader of the Jedi Order, and the rebirth of the Empire under Jaina Solo and her husband Jagged Fel. Who took over the Jedi in Luke's absence? How did Han and Leia handle the news of their daughter becoming a Galactic Empress? And what became of Han and Leia's granddaughter Allana, who was implied to be the true ChosenOne of the Jedi?
* ''Film/SupermanReturns'' ends with the rather divisive [[TheReveal Reveal]] that [[spoiler:Jason White is actually Superman's son, and that he's in the process of developing Superman's powers]]. Since the movie never received a sequel, and the films were [[ContinuityReboot rebooted]] with ''Film/ManOfSteel'' in 2013, we never got to see [[spoiler:what kind of man Jason would grow into, and how he would choose to follow in his father's footsteps]].
* ''Film/TotalRecall1990'': The ancient terraforming reactor on Mars. Even though one who believes that Quaid's spy adventure is fake can simply view it as a DeusExMachina to have him save the planet as part of his Rekall memory, it's still intriguing to speculate who could've built it and why. The film's novelization and the 2011 comic book sequel by Dynamite Entertainment offer different solutions about it being left by the ancient Martian civilization, but since in the movie the builders of the reactor are always referred to as "aliens", it could imply that some other advanced civilization came along and planted it before leaving for whatever reason, thus the possibilities are many.
* ''Film/TransformersFilmSeries'':
** An example from ''Film/TransformersDarkOfTheMoon''. By the third film, TheMasquerade is completely broken, and everyone is aware of the Autobots' existence. The movie doesn't go into much detail about this, but there are many ideas that can inspire a fanfic. One is how the nations of Earth are shown to dislike the Transformers (there's a mentioning of poll results stating that half the world would feel safer if the Autobots left). One must also wonder how other countries feel about the US using Autobots for non-Decepticon related problems (such as destroying illegal nuclear plants in the Middle East). Overall, there's a whole potential to explore how Earth must cope with the knowledge that one of the world's most powerful nations has HumongousMecha on its side, as well as the fact that said support also warrants even more alien attacks.
** There's also the matter of why Mikaela broke up with Sam.
** Before ''[=DotM=]'', there was a fairly large number of DayInTheLife-style fics regarding Ironhide and Captain Lennox's family. [[spoiler:[[KilledOffForReal Then]] ''[[KilledOffForReal Dark of the Moon]]'' [[KilledOffForReal happened...]]]]
* ''Film/{{Tron}}'':
** Due to her status as a SequelNonEntity in ''Film/TronLegacy'' (and material expanding on its canon), Yori has become a recurring element in ''Tron'' fanfic whether she is the focus or is only mentioned in passing. DependingOnTheWriter she either is in hiding as a rebel against [[spoiler:Clu]]'s dictatorship who survives the events of ''Legacy'', was killed during the initial coup or executed during the rebellion [[spoiler:(usually Clu has "Rinzler" do it in an ''epic'' level KickTheDog)]], was never brought over from the ENCOM servers to begin with, etc.
** After the third film was controversially cancelled, it has become very common for fans to write fanfics about [[spoiler:Quorra experiencing the human world after she escaped The Grid, or Tron after breaking free of Clu's rectification over him]].
** PatchworkFic with ''VideoGame/TronTwoPointOh'' elements became more common after the game was released on Steam. It's also common to do "what if" scenarios where Alan ends up investigating the arcade for himself and ends up "getting in."
* ''Film/WhoFramedRogerRabbit'':
** The history and origins of the {{Toon}} race.
*** The process of how a Toon is actually "born" or, perhaps "made".
** [[AlternateHistory Toons' effects on world history.]]
** Eddie and Teddy Valiant's careers as {{Private Investigator}}s.
** The early years of various Toon characters and how they came to know each other while getting their start in showbiz.
*** [[WhatDoesSheSeeInHim How Roger and Jessica met and fell in love.]]
*** Judge Doom's origin and StartOfDarkness.
** If Toontown survived into the present day, what does it look like now?
** The ending seems to open up the possibility that certain features of the modern world [[spoiler:(like freeways)]] don't take off in the movie's universe. How will that affect the state of the world (if at all)?
** The appearance of contemporary digitally-animated or computer generated characters. This may even include VideoGame characters.
** Toons from other countries (such as anime characters) and what their equivalents of Toontown are like.
[[/folder]]

[[folder:Anime and Manga]]
* The plot of ''Manga/AhMyGoddess'' begins when Keiichi accidentally dials the Goddess Relief Helpline and summons Belldandy. It's pretty easy to come up with a plot where someone (be it another cast member, an OriginalCharacter or even a character from another fandom) accidentally dials the Helpline, summons one of the goddesses (or even Mara the demon) and makes a wish, accidental or otherwise.
* ''Anime/AngelBeats'', just ''Angel Beats''. Let's see here...
** TheyWastedAPerfectlyGoodCharacter? How about an entire battlefront of characters? Literally, there were only [[spoiler:six characters]] with an actual {{backstory}} in the anime alone!
** ExecutiveMeddling: Because of this, [[Creator/KeyVisualArts Jun Maeda's]] original plan of 26 episodes were cut in half to 13!
** Let's not forget about how the Afterlife Battlefront came to be before Otonashi arrived. From the manga revealing how Yuri & Hinata started the battlefront to the first episode, this gap right here is ripe for fanfic writers to fill in!
** And then there's the ship teasing...
* ''Manga/AttackOnTitan'':
** Levi's past, prior to the release of ''A Choice With No Regrets''.
** The [[spoiler:Titan Shifters']] pasts and motivations.
** The following scenarios if Annie, or later [[spoiler:Reiner and Bertolt]] had succeeded in kidnapping Eren.
** Bertolt sleeping in strange positions.
** The events that led to [[spoiler:Marco]]'s death.
* ''LightNovel/ACertainMagicalIndex'': The sheer size of Academy City, number of unresolved plot threads, and the nature of Esper and Magic powers involving practically every area of physical science and fairy tale imaginable provides ample room for creating [=OCs=] and new storylines by eager fans.
* ''Anime/CodeGeass''. The sheer amount of ForWantOfANail moments, particularly when characters get ''this close'' to finding out someone's secret, make AlternateContinuity fanfics so compelling to explore. Not to mention the number of pieces in play...
* ''Anime/CowboyBebop'' persistently reveals a lot of background detail to the audience without actually telling them ''anything'', leaving enormous room for speculation. Most of this concerns the past relationship between Spike, Julia and Vicious, though other characters (especially Ein, Wen, and Mad Pierott) aren't exactly lacking.
* The ending of ''Anime/DaiGuard'' shows that Heterodynes will never stop coming even after the last one in the series is destroyed. That's several fanfics waiting to happen.
* ''Manga/DeathNote'':
** The Death Note has lots of rules that don't come up in the main plot. If someone's name is written in two Death Notes within a split second of each other, it is regarded as simultaneous and the victim ''lives'', unaffected by either note.
** {{Backstory}}: L's/Mello's/Near's/B's/Matt's [[DarkAndTroubledPast Dark And Troubled]] MysteriousPast. What does Wammy's House do and why was it built? / Light's career as a [[KidHero teen detective]] and/or [[ForWantOfANail what would happen if Light didn't find the notebook]] or [[WhatIf what would happen if]] [[spoiler:Light didn't get his memories back.]]
** The original short story was resolved by Ryuk giving Light a "Death Eraser", which could be used to erase names from a Death Note and thus bring them back to life. This item is not used or even mentioned in any adaptation (presumably it doesn't exist, since "[[AllDeathsFinal once dead, they can never come back to life]]"), but the idea is ripe for use in FixFic.
* ''Anime/DigimonAdventure'' has Wizardmon's MysteriousPast. What ''was'' his past really like? Where did he get his truckload of powers? What is it that makes him different from most Digimon? What was his relationship with Tailmon like?
* ''Franchise/DragonBall'' has lots of these.
** For example, the five years between ''Manga/DragonBall'' and ''Anime/DragonBallZ'', the time between the Cell and Majin Buu arcs, the years that Goku spent training with Kami, the years of training before the attack of the Androids 19 and 20... there are many others like those. Also, there is the fact that we know there were at least 20 androids created by Dr. Gero, but we don't know all of them; the fact that Saiyans were sent to other planets when they were babies to grow up with the planet's civilization to later destroy them and come back to Planet Vegeta, that left open the idea that there may be other Saiyans still alive, living in the planets they were assigned to destroy; the alternative Universe Future!Trunks came from, and the idea that more alternative dimensions can be created with the Time Machine... ''Dragon Ball'' is totally made out of fanfic fuel. But it was to be expected from a story of such length (and that was mostly improvised by Creator/AkiraToriyama!) and for all the {{Plot Hole}}s created by the anime series that needed to keep adding fillers while waiting for [[OvertookTheManga the manga to catch up]].
** It doesn't help either that almost all [[NonSerialMovie the movies]] could be considered {{Alternate Universe}}s because they don't fit very well with the main continuity, so you have many possible universes to tell stories about.
** For ''Anime/DragonBallSuper'', fans are coming up with ideas and stories about [[spoiler:what happens to Future Trunks and Mai after they leave for the new timeline, like Future Trunks training with Alt-Future Trunks]]. Likewise, some are coming with ideas for how Trunks will deal with Beerus on his own timeline.
** Like with the previous series, some fans like to imagine what would the different kind of Saiyan transformations look on the new Saiyans introduced in ''Super''. Goku Black, in particular, has a lot of fans who like to imagine how would he look like as a [[Anime/DragonBallGT Super Saiyan 4]] or with the Ultra Instinct.
** In general, the many cool fighters from the Tournament of Power got fans who like to imagine backstories for many of them.
** One can easily make a fanfic for ''VideoGame/DragonBallXenoverse2'' enough to make their own canon. Such as the first Time Patroller being their parent[[note]]If you decided this case, then you can easily create the idea of them being raised in the Hyperbolic Time Chamber, or due to the nature of one of the late-chapters, having a possession of a Time Ring and Supreme Kai earring to avoid a RetGone[[/note]], siblings, or senpai. The possibilities are endless. Heck, Creator/TeamFourStar themselves made the idea of their original character being the father of their ''[=XV2=]'' character. [[note]]Puddin, their ''[=XV2=]'' character is the daughter of Dumplin and Towa.[[/note]]
* ''LightNovel/TheFamiliarOfZero'':
** The series starts with Louise summoning a familiar, and accidentally summoning a human from another world. ''Every single fanfic'' starts by simply changing who she summoned, usually as a {{Crossover}} with another 'verse. It's notable enough that our fanfic sub-forum on this very wiki has a thread dedicated solely to collecting interesting ''Zero'' crossovers.
** Even when the summon doesn't actually change, the entire ''Zero'' universe is fuel. A Low Middle Ages/Early Renaissance set, with magic and elves? The possibilities are endless (specially when the writers do their history homework).
* ''Franchise/{{Gundam}}'': Even the original ''Anime/MobileSuitGundam'' made it clear that what was shown on screen was simply one small part of a large war. The UC timeline spans over two centuries, and then there are the AlternateUniverse series, and that's not even considering fans making their own ''Gundam'' AU. There's also less of an aversion to fans making up all-new casts due to the practice of introducing a new lead character for every anime, manga and video game.
* ''Webcomic/HetaliaAxisPowers'':
** Fans have plenty of fun writing for the nations, with all the history between them.
** The vast amounts of ShipTease and HoYay between nations (in part due to the main cast being [[CastFullOfPrettyBoys almost entirely male]] and AmbiguouslyBi) has lead to many works putting popular (and in some cases [[CrackPairing not-so-popular]]) pairings together, either as Nations, or in a human (usually high-school) AU. The fact most of them has at least one human name suggested by WordOfGod helps the latter significantly.
** The nature of being a Nation is touched on briefly in the series, but much is left up for speculation - like what exactly leads to a Nation's 'disappearance', how emotionally damaging is it to be immortal and how being forced to comply with their bosses' wishes (as is implied with WWII-Germany) affects them.
* ''VisualNovel/HigurashiWhenTheyCry'':
** Similar to the above, the reveal that each arc is in fact a different universe, with [[spoiler:Rika and Hanyuu]] hitting the ResetButton every few weeks opens up a lot of potential -- [[CashCowFranchise which even the creators have latched onto.]]
** Post-''Kai'' fan works are also popular, due to potential plot lines left hanging, [[spoiler:like whether Satoshi will ever wake up, what happens to [[VillainousBreakdown Takano after she is]] [[RedemptionEqualsLife rescued by Tomitake]], and what Toyko will do next]].
* ''LightNovel/InfiniteStratos''. For the average viewer, it's just a mediocre UnwantedHarem [[RecycledInSpace WITH]] [[InstantAwesomeJustAddMecha MECHA]]. [[VocalMinority Fan Fic writers on the other hand]]... War, politic, social shift... the potential is limitless, and three point above is rarely addressed in the canon source (except small clues here and there) despite it was said the introduction of titular PoweredArmor [[InformedAbility more than few things changed]], leaving the gap for the fic writers to explore. It was not rare to find the sheer difference of atmosphere in I.S. fanfic as the result, from RomanticComedy[=/=]{{Shipping}} to GrimDark WarFic, despite the [[SugarWiki/NeedsMoreLove tiny size of the fanbase]].
* ''Manga/JoJosBizarreAdventure'': It's extremely common to find fanfic and fancomics starring a grown up Shizuka from ''[[Manga/JoJosBizarreAdventureDiamondIsUnbreakable Diamond is Unbreakable]]'' with her as the lead Joestar of the original "Part" that the fanfic author creates. This is probably due to a desire to create more content for the original universe without having to add to the already convoluted Joestar family tree, as well as [[GodNeverSaidThat a longstanding rumor that she would have been the protagonist of]] [[Manga/JoJosBizarreAdventureSteelBallRun Part 7]] [[GodNeverSaidThat before Araki decided to reboot the series]].
* ''Anime/KillLaKill'':
** A rather funny example from Episode 21: Mako tells Aikurou that she was able to remember Satsuki's plan so well because Satsuki had written every detail on her hands. Cue fan artists making a very intimate scene of Satsuki writing the instructions on Mako's hands.
** There's the question of what exactly happened to Rei after [[spoiler:Senketsu separates her from Shinra-Koketsu... It gets answered in #25.]]
** The alternate life the characters would have had if Ragyo didn't use her children to test the Life Fibers and abuse them or, alternatively, if the Life Fibers haven't existed.
** The backgrounds of Satsuki and Nui are also explored in fanfiction, especially with Satsuki's with [[spoiler:her mother's abuse]], along with the effects thereof. In that line, we get Ragyo's backstory being subject of at least a few, seeing as it has never been seen in the series.
* ''Manga/MedakaBox'' briefly mentions the other "main characters" between Iihiko and Medaka, who came along once every thousand years, and would have to have at least as much SuccessThroughInsanity as those two, though they would all be DoomedByCanon since [[spoiler:Iihiko killed all of them]]. Additionally, the whole cast have intricate backstories just waiting to be filled in.
* The basic premise of ''Manga/MonsterMusume'' is that the government revealed the existence of monsters to the world and created cultural exchange programs, with some humans being sent to live with monsters and monsters being sent to live with humans. As a result, several fan stories revolve around an OriginalCharacter (maybe more) receiving several monsters and having to adjust to life with their new housemates.
* ''Anime/MonsterRancher'': Unlike the other members, [[TheTrickster Hare's]] past prior to meeting up with the Searchers was not touched upon until a single episode partway through the final, PostScriptSeason, making it a common target for speculation.
* ''Manga/{{Naruto}}'':
** The fandom already were fond of writing AlternateUniverse fanfiction set in high school but when the anime released an ending theme that pretty much set up the roles of each character for them the amount of fanfiction (and fanart for that matter) exploded.
** And then, thanks to ''[[Anime/NarutoTheMovieRoadToNinja Road to Ninja]]'' and the [[spoiler:possibility for a LotusEaterMachine Jutsu]], these Alternate Universes have more weight to them.
** There is also the 1997 pilot chapter, which not only has Naruto as an actual kitsune, but also has the attacking Nine-Tails as his ''father.''
** Among Naruto's graduating class at the Academy, we know of only three ninja teams that were formed: Team 7, Naruto's team; Team 8, Hinata's team; and Team 10, the Ino-Shika-Cho trio. (Team Gai is one year ahead of them.) That leaves at least seven other possible teams (1 through 6 and 9), and very likely more than that, of whose exploits we know nothing and for whom potential story ideas are ripe for the picking. [[note]]For perspective, we know that Itachi was a member of his class's Team 2, and in ''Anime/{{Boruto}}'' there are up to 40 teams from Boruto's class.[[/note]]
* ''Anime/NeonGenesisEvangelion'': Its controversial plotline that only got more MindScrew-y as the show went on, a very ambiguous mythology surrounding its setting, and a cast chock-full of {{Woobie}}s who get pushed to (and sometimes past) their breaking points makes this anime a fertile ground for fan writers to step in.
* While any one-shot character from ''Anime/OjamajoDoremi'' has this, Nozomi and [[KidFromTheFuture Fami]] get this the most since they had a lot of potential as characters and several loose ends.
* ''Anime/PokemonTheSeries'':
** Three words: Ash Ketchum's [[DisappearedDad father]]. There's a good reason [[WMG/PokemonAshsFather it has its own WMG page on TV Tropes]].
** The revelation that Ash's new traveling companion in the ''[[VideoGame/PokemonXAndY X/Y]]'' series, Serena, is ChildhoodFriends with him. Certainly opens up new possibilities/insights into Ash's childhood, and that's before considering the shipping factor (a discussion thread for the pairing was already into triple digits after only ''seven'' episodes).
** "The Cave of Mirrors!" ([=XY037=]) confirms the existence of a MirrorUniverse where everyone's MirrorSelf exhibits personality traits opposite of their regular versions (but not [[BizarroUniverse a complete flip-flop]]). As only the mirror counterparts of Ash, his current traveling companions, some of their Pokémon, and Team Rocket are shown, this leaves the door wide open for Mirror World incarnations of other characters. For that matter, how would the ''X/Y'' saga differ ([[InSpiteOfANail if at all]]) because of said characters' differences in temperament and ability? How would this affect Ash's past and future journeys?
** ''Anime/PokemonLucarioAndTheMysteryOfMew'' shows that Ash has enough Aura to be able to activate multiple Aura artefacts. Since this is in a movie, many would think that Ash's Aura potential would be forgotten...until we come across two episodes of the series that reference Aura in such a way that implies that Ash's adventures in Rota Town happened in some form. "He's using his Aura unconsciously" has become a very valid explanation as to how Ash does most of the things he does.
* ''Anime/PrincessPrincipal'' had 12 episodes, shown in AnachronicOrder, with case numbers going up to 24, meaning half the numbers are missing. What happened in the cases not shown?
* ''Anime/PuellaMagiMadokaMagica'':
** WordOfGod confirms that [[spoiler:Homura]] underwent approximately 100 timeloops before the start of the series, which opens up a lot of potential for alternate timeline fics.
** The sheer [[AmbiguouslyGay ambiguity]] of the relationships between the girls (particularly Kyoko for Sayaka and Homura for Madoka) opens up a whole can of {{Fix Fic}}s that [[UnusualEuphemism tramples any ambiguity so far into the ground that its Soul Gem shatters]].
** The nature of the MagicalGirl cycle is this: allowing practically any girl to be a MagicalGirl, abilities that straddle the border between ImaginationBasedSuperpower and NewPowersAsThePlotDemands, the various [[AwfulTruth truths]] that [[ManipulativeBastard Kyubey never mentions]] and the in-universe speculation that hope and despair [[EquivalentExchange must balance out in the end]], culminating in [[spoiler:[[AndThenJohnWasAZombie the transformation into a witch]]]] -- the {{Tragic|Hero}} {{Original Character}}s practically write themselves.
** ''Anime/PuellaMagiMadokaMagicaTheMovieRebellion'': WordOfGod is that they wanted the viewers to imagine their own sequel to the movie. The movie's ending has enough ambiguity to facilitate a number of different plots. The beginning of the movie can also fit [[spoiler:as it's the only time we see the five magical girls living a happy, idyllic existence]].
** ''VideoGame/PuellaMagiMadokaMagicaPortable'': Two highly enigmatic witches are introduced in this game, one who [[spoiler:cosplays as Kyubey]] and the other who [[spoiler:comes from an alien magical girl]]. These facts are revealed, but not really explored, raising a lot of questions for the fans.
* ''Manga/RanmaOneHalf'':
** The Jusenkyo Springs provide various opportunities for plots: What if Ranma fell into a ''different'' spring? What if one of the other characters (or an OriginalCharacter) fell into a spring? What if a character from a different fandom fell into one of the springs?
** Also, the franchise's love of the "Someone from ____'s past (usually Genma) comes to Nerima looking for answers and/or revenge" plot. Rememeber, Genma and Ranma were WalkingTheEarth for years. The possibilies for new characters and/or crossovers is just as vast (if not bigger) than the Jusenkyo Springs.
* ''Anime/{{Robotech}}'', covering three generations and two post apocalypses.
** The years it takes the SDF-1 to get back to Earth leaves lots of room for how Robotechnology and the knowledge of aliens effects geo-global politics back home.
** Reconstruction Blues, Mad Max meets Robotech has unlimited potential.
** The Second Robotech War; the series follows the main character sure, but how is the war effecting the rest of the world which would be a mix of first world and third world conditions.
** The Invid occupied Earth, Mad Max meets Robotech all under the shadow of slavery by the Invid and the Flower of Life's take over of the Earth devastated ecology.
** And while the Sentinels books and cartoon episode covered what happened to the SDF-3, a lot of people consider it FanonDiscontinuity, so there is ample room to re-write what happened to the SDF-3.
* ''Franchise/SailorMoon'':
** ''Sailor Moon'' spans millennia and follows only a dozen or so girls of what could be hundreds. Naoko did say that there could be senshi all over the universe, and we even meet a couple dozen alien senshi in the last arc/season. Therefore, there's ''reams'' of Silver Millennium, Crystal Tokyo, and "Team Other Than The Sol Senshi" stories out there, and the pile grows all the time. Basically, for any celestial body, there's a Sailor for that.
** There's also Jadeite's [[Anime/SailorMoon anime]] fate. When Beryl pulled a YouHaveFailedMe, she sentenced him to [[spoiler:"Eternal Sleep." No, that's not a dub edit.]] Such a thing seems to ''scream'' "dramatic return someday down the line," especially as it turns out that people in this series [[spoiler:can actually die, so no death stand-in or euphemism is needed if he was truly intended to be dead]]. So the series has a 200-episode (plus an OVA or two) run and ends with no such dramatic return, well, it kinda seemed like an oversight, and fans have been correcting it ever since. He's not even that remarkable a villain and doesn't get much in the way of CharacterDevelopment; it just feels so ''wrong'' when ChekhovsGun doesn't get fired. On the other hand, the [[Manga/SailorMoon manga]] Jadeite is pretty definitely dead.
** How about Mimete's fate? The last we see of her, she's [[spoiler:trapped in a computer when Tellu pulls the plug]], so unless it's stated otherwise, [[spoiler:all someone would have to do to get her back would be to turn the computer on again]].
* For ''Anime/StrikeWitches'', there exist plenty of non-eroge doujins about the many Witches from around its world. This is set as an alternate timeline of World War II, and the anime only covered a small portion of its European nations. Just think about all the potential there is for fan fic writers and doujinji artists.
* The Aincrad story arc of ''LightNovel/SwordArtOnline'' focuses almost exclusively on Kirito and his unintentionally-gathered [[BattleHarem harem]] of [[GamerChick female players]]. But even including all of the side characters from that arc, they are only perhaps 20 out of the ''ten thousand'' unnamed, off-screen players who were trapped in Sword Art Online for two years. Nearly all of whom were gamers. The sheer volume of [[SelfInsertFic self-insert]] and [[OriginalCharacter OC]] [[FanFic fanfic]] rivals many longer-running series.
* ''Manga/TsubasaReservoirChronicle''. [[spoiler:[[AndTheAdventureContinues Non-ending?]]]]. Check. Not resolving any ships at all? Check. Mysterious characters? Check. Massive potential for crossovers with just the feather as the price? Check. Tsubasa is made of this trope, now, if only [[YaoiFangirls the fan fiction writers]] [[AlternateUniverseFic would use it.....]]
* The plot of ''Manga/UruseiYatsura'' is kicked off when Ataru is chosen to be Lum's opponent in a game of tag in order to save the world from being conquered, and [[AccidentalProposal accidentally becomes engaged to her]]. It's pretty easy to come up with a plot where another teenaged character, either from the same series or from a different fandom, is the one chosen to challenge and accidentally propose to Lum.
* ''Anime/TheVisionOfEscaflowne'' never expanded on the Zaibach Empire, or the backstories of Dilandau, Jajuka, and other Dragon Slayers. Luckily, the fans are more than happy to step in and do it themselves.
* ''Franchise/YuGiOh'':
** The Virtual Nightmare Arc in the original ''Anime/YuGiOh'' was supposed to be a FillerArc, but it introduced a unique [[HouseRules House Rule]] to the game called the Deck Master system. Despite Kaiba's insistence canon-wise that [[LetUsNeverSpeakOFThisAgain they forget it ever happened]], FanFic writers never seem to get tired of using this house rule and putting unique spins on it. (In fact, ''VideoGame/YuGiOhTheDuelistsOfTheRoses'' may have been a "legit" example of expanding the Deck Master system with the similarly functioning Deck Leaders.)
** Both Bakuras are absent in ''Anime/YuGiOhTheMoviePyramidOfLight'', so naturally there are several theories and fanfics about where they were.
** In ''Anime/YuGiOhGX'', Daichi Misawa has six different decks in the first season (not counting a "practice deck" he uses in his entrance exam and the "7th Deck" he uses against Judai) but he only uses two of them over the course of the series, and the themes and strategies of the other four remain mysteries. A ''lot'' of fanfics that feature him explore this further, each author giving opinions on what at least some of them are.
** And on that note: Fire Dragon. The first OP shows him flanked by two monsters: Water Dragon, a dragon made of water that we do see him use, and a similar monster made of fire, that we do not, nicknamed Fire Dragon by fans. Some take his later monster Carbogeddon to be related to it (since Water Dragon is created from two Hydrogeddons and one Oxygeddon), but it was never elaborated upon.
[[/folder]]

* ''ComicBook/DisneyKingdoms'': Seeing as an official third series about them never saw the light of day, what adventures will Dreamfinder and Figment go on after the events of ''Figment 2''? Will they find the lost geodesic sphere?