* ''Series/TwentyFour'':
** Though only David Palmer had his political party association openly identified onscreen (he's a Democrat), fans have gone on to identify the series later presidents parties based upon this initial info.
** John Keeler, having run against Palmer, is a Republican, as is Charles Logan, who was Keeler's vice president. Same goes for Hal Gardner, who succeded Logan.
** Wayne Palmer, having served as his brother's White House chief of staff and WordOfGod says defeated Gardner in the next election, is a Democrat. Sames goes for his VP, Noah Daniels.
** Allison Taylor, having defeated Daniels in the next election, is a Republican.
** James Heller, who was Keeler's secretary of defense, is also presumed to be a Republican.
* ''Series/AbbottElementary'': Most fans headcanon Melissa as gay or bisexual, mainly due to {{shipping}}[=-=]related reasons. In the actual series, Melissa has only been shown in relationships with men.
* ''Series/TheAddamsFamily'':
** There is a mounting wave of fanon locating the family's home somewhere in New Jersey -- sometimes in the midst of the Pine Barrens, sometimes in Edgewater, and sometimes in Creator/CharlesAddams' own hometown of Westfield.
** The series is deliberately vague about the specific nature of the Addams clan's..."eccentricities", prompting much speculation among fans about what they actually ''are''. Many fan works are written under the assumption that Morticia is a vampire, Fester is a zombie, and Lurch is an artificially created human (''à la'' FrankensteinsMonster), none of which is ever definitively established in the show.
* ''Series/AgentsOfSHIELD'': Until {{Canon}} says otherwise, the fandom (and ''especially'' the fanfic writers) takes an EveryoneIsBi stance on the team of young, attractive agents.
* The ''Series/{{Alias}}'' fandom was eaten alive by various pieces of fanon that rapidly became totally disconnected from the actual characters and events seen on the show, especially where Irina Derevko was concerned. Many of these were ship-related, but not all, and enormous fury was unleashed when it became clear that the series had no chance of following the path the fanon assumed.
* ''Series/BabylonFive'': Although not strictly speaking canon, the generally accepted theory is that [[spoiler:Delenn went Beyond the Rim at the end of her life and [[TogetherInDeath joined Sheridan]] (and Sinclair) there]].
* ''Series/{{Battlestar Galactica|2003}}'':
** Fans have been known to take a deleted scene where Elosha refers to a jealous god starting a war on Kobol as canon -- despite it being, y'know, ''deleted'' -- and thus extrapolating that the Thirteenth Tribe were monotheists. The most current WordOfGod is that they were polytheists like the others (as evidenced by their Temple of Aurora), and the exodus from Kobol was the result of man "stealing fire" from the gods by creating life. The last five survivors of the Thirteenth Tribe became monotheists after meeting the monotheistic Centurions.
** There was also a very common misconception that Tigh and Adama had served together during the First Cylon War. This was actually shown not to be the case in Season 2, Episode 1, [[Recap/BattlestarGalactica2003S02E01Scattered "Scattered"]]. They met years after the war, on a freighter. It apparently didn't register with many fans, which is why there was a general uproar when [[spoiler:Tigh turned out to be a Cylon]].
** No one's ever said there are twelve Lords of Kobol, but it's taken for granted by many a fan. Given that they've mentioned gods outside the traditional twelve Olympians and have only used "Lord of Kobol" as a synonym for "god", not a subset, there are probably more than twelve. ''Series/{{Caprica}}'''s online in-universe newspaper, ''The Caprican'', establishes that Illumini, the second major city on Gemenon, is built around a huge pantheon devoted to dozens of deities.
*** In the Original Series episode "Lost Planet of the Gods", it is explained that the Lords of Kobol were the leaders of that highly advanced civilization until they are wiped out in a vaguely-mentioned ecological disaster. Long afterward, they were deified by their descendants, the inhabitants of the Twelve Colonies. The last Lord of Kobol was the Ninth Lord of Kobol, into whose tomb Adama enters looking for a map to Earth (which he finds, and which is then immediately destroyed when the Cylons attack Kobol). Side-note: In order to enter the tomb, Adama uses his Council of Twelve Badge of Office as a key. The other surviving Council Members also had them, but didn't seem to realize their true significance, and Council Members elected after the Destruction didn't have them.
** Leah Cairns (the actress who played Racetrack) mentioned in several interviews that she believed her character had UnresolvedSexualTension with Helo (who was a former Raptor pilot himself), and that she purposely played Racetrack in this mindset during the show. It's never been overtly suggested what's going on between Racetrack and Helo (even though there are a couple of broad hints), but most fans consider that fact canon.
*** This particular example is fanon becoming quasi-canon. Cairns was shown a Racetrack/Helo fanfic, and found the idea of her character having UnresolvedSexualTension with Helo hilarious... but also interesting. So she threw that characterization into her performance.
* ''Series/TheBigBangTheory'':
** Sheldon displays classic signs of Asperger's Syndrome, but the creators have shot down that idea (WordOfGod has it they didn't want to pin him down with a specific issue, so as not to fall victim to UnfortunateImplications). It doesn't stop the fans from making this guess though.
** And now the idea that Sheldon is asexual is being pushed on Tumblr. But Sheldon has shown that he's attracted to Amy, and he no longer has a problem calling her his girlfriend. He may or may not act more on the attraction, but it's safe to say that he's not asexual. [[WildMassGuessing He could only be ''romantically'' attracted to Amy, though...]] Eventually, they do have sex, with Sheldon initiating it.[[note]] It was a birthday present for her in Season 10, and later it's stated that normally they only do it on her birthday.[[/note]]
* ''Series/BlakesSeven'': [[spoiler:Vila]] is not dead. He fell backwards, therefore he is still alive.
** Gan is from the planet Zephron - a piece of fanon so widespread it even appears in his Wikipedia article. He's usually a Gamma grade, though some fics have him as a Beta. A very common but now discredited trope had Avon as an extra-special alpha (Silver Alpha, Alpha-Plus....
* ''{{Series/Bones}}''
** There’s a contingent of fans who are convinced Aubrey and Jessica got back together as a couple after the show ended. Especially since breaking up and reuniting wasn’t uncommon for couples on the show.
** Fics where Hodgins and Angela have a baby girl usually call her Katherine or Katy based on what they wanted for a girl’s name in season 6. Jeffery is popular for a second boy because it’s Jack’s brother’s name.
** If Booth or Brennan die in a fic, the other will almost always follow very quickly. Fans hate to think of them being separated even in death.
** Future-set fics often pair up Michael Vincent and Christine.
* ''Series/BuffyTheVampireSlayer'':
** Fandom reacted badly to Andrew being seen heading off for a night on the town with two attractive women, since he's "obviously" gay; it's actually [[AmbiguouslyGay more ambiguous]] with hints of possible bisexuality. Creator/JossWhedon has since stated that [[http://whedonesque.com/comments/15286#207889 Andrew was supposed to be headed off for a night on the town with a mixed-sex group]]. Remember, it's Italy.
** There's also the fanon that Spike absolutely hates his last name, Pratt. Admittedly, since he never mentions it and goes by William the Bloody, which was actually an insult, before going by Spike, it's logical. (Also, "prat", usually with only one t but it makes no difference to the pronunciation, is slang for "idiot" in Britain.)
** There was a belief among some fans that "Buffy" was a nickname, and the Slayer's "real" first name was actually "Elizabeth". This has been {{Jossed}}--most notably by [[spoiler:''her grave stone'']], but there still seems to be a faction that clings to it (in the real world, "Buffy" derives from "Elizabeth" through the toddler mispronunciation "Ewizabuff").
** After she came out during the fourth season, the fandom quietly decided that Willow had a huge crush on Giles' girlfriend Jenny during the second season. It's one of those things that just makes ''sense'', what with Jenny inspiring Willow to start dabble in magic, the thing that later would become a not-so-subtle metaphor for lesbian sex. It is also canon that Willow has called Jenny her favorite teacher during that time frame. Given that Jenny was the computer teacher, she may have also inadvertently helped initiate Willow's hacking abilities too. Whether she had/has similar feelings for Buffy is debatable.
*** S8 makes it a little less debatable since Willow grills Satsu on what Buffy's like in bed (including how she sounds when she orgasms). [[BlatantLies Then she denies ever having a crush on Buffy]] to Buffy after telling Buffy to be careful with Satsu. Buffy in turn, almost petulantly, denies having a crush on Willow because Willow denied to Buffy first. Later on, in another issue, Kennedy starts showing jealousy, telling Buffy, "But you put the moves on Red and I'll kill you like a chicken."
--->'''Willow''': And just so you know... I never wanted to sleep with you either.
--->'''Buffy''': What are you talking about?
--->'''Willow''': I'm sayin' it's a good thing you didn't try your little experiment on me. 'Cause it wouldn't have worked, Summers. You're not even on my list.
--->'''Buffy''': What list? There's a list?
--->'''Willow''': Yep. And you're not on it. Not my type.
--->'''Buffy''': Oh, yeah? Well, then, you're not on my list either!
--->'''Willow''': Good. I don't want to be.
--->'''Buffy''': Sure you do. It's a very distinguished list. It has people like um...Creator/JudiDench and UsefulNotes/EleanorRoosevelt on it.
--->'''Willow''': Eww. Just got the visual.
--->'''Buffy''': And other people too. Those are just examples off the top of my head.
*** Then there's season 9 which opens with Buffy after a night of drinking and partying, thinking she did the naughty with Willow and her ''very heavily'' suggesting they did. This was after asking if her married ex had porn then tried hitting on him. [[spoiler: This was right at the time Andrew brought back the Buffybot and put Buffy's mind into it in a bid to lure out the BigBad, so not only can her behavior be excused on account of being wonky, if Willow was serious about sleeping with Buffy then she did it with the bot, not the Slayer, [[MindScrew kinda]].]]
** Many Spike-centric fanfics tend to mention Angelus sodomizing Spike at some point during their eighteen years of being in 'The Whirlwind" together, but this is never mentioned in canon. In fact the only time it was even hinted that they had any kind of sex is in Angel, season 5x21 'Power Play', when Spike balks at being called Angel's 'intimate' by Ilyria, but then amends it:
--->'''Spike''': Angel and me have never been intimate. Except that one...
*** Joss Whedon has also stated that Angel and Spike have had at least one sexual encounter, which technically makes this pairing canon, but there was nothing to hint at it being non-consensual.
** Fanfic tends to portray Anya and Tara as best friends, since neither canonically had one.
** Conventional wisdom is that Anya starting life as a human was a {{Retcon}}, but this was in fact part of the character from her first appearance. Giles refers in "The Wish" to the destruction of her power center making her an ordinary woman ''again''. The original script, available on the DVD, included a line about her becoming Anyanka after she summoned a demon who cursed her.
** There is also a common idea that vampires can choose "mates" from the humans around them. Not "mates" in the sense of turning someone into a vampire for companionship, but that a human can be bitten and marked by a vampire, thus taking a form of ownership over that particular human. This would, in turn, offer a sort of protection from other vampires, who would sense the mark, and leave that human alone. There is nothing, repeat ''nothing'', in the Buffy or Angel series that indicates a vampire could do this, or would even be inclined to do so. They are much more likely to either kill or turn a person.
*** There's more fanon about Buffyverse vampires. Like that they have a psychic connection with the vampires they sire, which is ''sometimes'' true, but that only showed up once, and even then it was only in the form of Angel [[PsychicDreamsForEveryone dreaming about the other vampire's kills]]; it didn't let Angel control him as it does in fanfiction. The fandom also seems to believe that a newly turned vampire is called a 'fledgling.' They are never once referred to as such in canon. Also, while vampires do get stronger with age, there's no particular point at which a vampire becomes a 'master'; it just seems to be a general term used for the leader of a large group of vampires, who is typically the strongest because vampires usually operate on KlingonPromotion and AsskickingLeadsToLeadership.
** Dawn's middle name was never revealed during the course of the show. An early ''Buffy'' fanfic writer decided that her middle name was "Marie", and it spread to the point that you won't find too many examples of ''Buffy'' fan fiction that, if her full name is recited, doesn't have her named Dawn Marie Summers.
*** This has since become AscendedFanon. During a Q&A, one fan asked Creator/JossWhedon if it was true that Dawn's middle name was "Marie" and he sort of shrugged and said, "Sure, we'll go with that. Dawn Marie Summers." He then made a hand movement that was vaguely like crossing one's self and said, "[[GratuitousLatin Pax vobiscum]], its official. Her middle name is Marie."
** Many fans have taken the statement that "no weapon forged" can kill the Judge to mean that he is specifically immune to weapons that were forged, and the reason a rocket launcher was able to kill him is because it was ''manufactured''. This is not actually strictly contradicted in the series, but Buffy's line, "That was then. This is now.", and the fact that the Judge was apparently cut to pieces in the past seems to indicate that the line was ''descriptive'' rather than proscriptive, and it's simply a case of weapons technology having advanced to the point that a text written hundreds of years ago is no longer applicable. Additionally, it's only stated that the Judge cannot be ''killed'' by any weapon, not that they cannot harm him at all.
** A less popular but not uncommon piece of fanon is that Tara and, by extension, Willow were stoners. This is supported only by Tara wearing a shirt with a marijuana leaf on it in one episode and a line in a later episode that implied the two watch ''WesternAnimation/SpongebobSquarepants'' while high. Flimsy prompting, yet the fanon seems to have caught on.
** It's pretty accepted that Dru and Spike did each other's make-up (and hair dye) thanks to Drusilla's eyeliner game being perfect even with no reflection.
** The [[TheMusicMeister villain]] of the MusicalEpisode is not named ([[IHaveManyNames though he mentions having a hundred]]), but the credits say "Sweet makeup by..." Fans thus started calling him "Sweet," which became AscendedFanon when "Walk Through the Fire" got an official music video.
* The ''Series/{{Community}}'' episode "The Psychology of Letting Go" features a well-known background gag where Abed helps deliver a baby in the parking lot at Greendale--which is [[UnusuallyUninterestingSight never acknowledged or remarked upon]] until near the end of Season 2, when [[ContinuityNod he casually mentions it]]. Fans eventually noted that "The Psychology of Letting Go" originally aired just over 9 months after "The Politics of Human Sexuality", which ends with Abed making a PA announcement [[ItMakesSenseInContext encouraging everyone at Greendale to have unprotected sex]] (right after Dean Pelton accidentally gives away hundreds of faulty condoms). Since then, it's become generally accepted by fans that the woman in the parking lot was one of the Greendale students who got pregnant at the STD awareness fair.
* ''Series/{{CSINY}}'':
** Many fics have Claire pregnant when she died on 9/11 even though there is no canon evidence for it.
** Also common is the idea of Claire having amnesia or faking her death on 9/11, fueled by the lack of a body being found (though in reality, many 9/11 remains simply can't be ID'd with current technology, so no body doesn't mean no death.)
** It was fanon for a while that Mac's full name was [=McCanna=] Boyd Taylor, Jr. after that was revealed as his father's name in Season 5. However, that got {{Jossed}} in Season 8 -- his middle name is Llewelyn.
* ''Series/DarkAngel'': Many, many, many fanfics have other transgenics refer to Max and her siblings as "the '09ers" because they escaped in 2009, even though this nickname appears nowhere in the show.
* ''Series/{{Debra}}'': That the main character Debra Delong is on the autistic spectrum based on her various traits in the show.
* ''Series/DoctorWho'':
** That the First Doctor's showy ring acts as some kind of psychic or technological link to the TARDIS. This is possibly implied in a couple of scenes by Hartnell's performance, but never actually stated. Certain expanded universe stories turn this into AscendedFanon.
** The idea that the War Chief and the later-introduced Master, who share many similarities, are [[TheNthDoctor one and the same]]. Some ExpandedUniverse works say they are, and others say they're not.
** The idea that the Doctor's home planet Gallifrey is relatively time-locked to Time Lords' individual timelines. Meaning that if a Time Lord takes a TARDIS, leaves Gallifrey, and spends two years in his/her personal time-line traveling to the formation of the Universe and to the End of Time, he or she can only return to Gallifrey two years after departure, missing what happened in-between on Gallifrey (although this can be overridden in special circumstances, as with "The Five Doctors" and "The Day of the Doctor"). This can explain the Cloister Bell that warns Time Lords that something is going to hell on Gallifrey, since they need to travel there NOW in order to be of any help. This also neatly explains why all the Gallifrey-set stories seem to follow SanDimasTime in relation to each other and in relation to other locations within each story. It also has zero explicit evidence in the show itself.
** Related to the above is the idea that Time Lords' individual timelines are relatively locked, explaining why the renegades usually meet in chronological order. "Time and the Rani" supports this, as a plot point relies on the Doctor and the Rani being the same age; "World Enough and Time"/"The Doctor Falls" contradicts it, with the Twelfth Doctor and Missy [[spoiler:meeting the Saxon Master]]--of course, it's hardly unlikely that the Master could've done the impossible.
** There was a common dark fanon that Barbara Wright died early from cancer, contracted due to being irradiated on Skaro in "The Daleks". This was largely inspired by the fact that her actor, Creator/JacquelineHill, had died from breast cancer in her early sixties in real life. Creator/RussellTDavies disliked it enough to contradict it in canon with a line of dialogue in ''Series/TheSarahJaneAdventures'': "Death of the Doctor".
** In "Spearhead From Space", it is revealed that the recently-exiled-to-Earth Third Doctor has a tattoo[[note]]actually Jon Pertwee's from his days in the Royal Navy[[/note]]. As the Doctor (and the Third especially) has never seemed like the type to be into body-art, nor has the Third Doctor really had much time to hit up the tattoo parlours at this point in the story, fans tend to assume that is is in fact a mark given to him by the Time Lords branding him as a criminal and exile.
** Almost all fans with knowledge of the Third Doctor era accept the fanon that K'anpo in "Planet of the Spiders" is the same person as the wise old hermit the Doctor reminisced about to Jo in the previous season's "The Time Monster". The two stories share the same writers and heavy Buddhist subtext, so it isn't implausible, but it's never explicitly stated.
** A popular fanon theory speculates that the Doctor and the Master were brothers, before Creator/RussellTDavies made very clear that it wasn't so. The show itself even poked fun of the clichedness of the theory in the new series. However, this is an idea that has been around since the 1970s, and the Doctor lies...
*** In "The End of Time," the Master mentions "my father" while talking to the Doctor, so most likely they're not full blood brothers. Whether they're half-brothers or some other relation...
** In the [[Franchise/DoctorWhoExpandedUniverse EU]] sections of fandom, it is almost universally believed that the Ninth Doctor's leather jacket originally belonged to [[Literature/EighthDoctorAdventures Fitz]]. %% This theory still holds some water even after the reveal of the War Doctor - don't remove it based on that.
** FixFic for Donna's fate in "Journey's End" tends to rely on the premise that removing (or blocking, in most of these fics) Donna's memories didn't undo the meta-crisis. And since alt!Ten ''can't'' regenerate -- well, the regen capability had to go somewhere, didn't it? Cue regenerating!Donna fic galore.
** The idea that looking into the heart of the TARDIS made Rose unable to age has become so pervasive that when she shows up in fanfiction that takes place several years later still looking like she's nineteen, many authors don't even bother to explain why.
** It is probably inevitable that a lot of fan art of the Twelfth Doctor has him as SirSwearsALot, due to Creator/PeterCapaldi's role as Malcolm Tucker in ''Series/TheThickOfIt'' and ''Film/InTheLoop''.
** That the lighter-armoured "noble" Ice Warriors are called Ice Lords. This did turn up in later Expanded Universe material, but it started out as WordOfDante from ''Magazine/DoctorWhoMagazine'', back when they were ''Doctor Who Weekly''.
** That Dalek guns can kill Time Lords completely without allowing them to regenerate. This persists even after it was partially disproven on screen in "The Stolen Earth".
*** In addition, plenty of material shows that ''lots'' of things can kill a Time Lord without allowing them to regenerate.
** [[http://dreaming-of-the-second-sun.tumblr.com/ The Gallifreyan Tradition Society]] relies heavily on this.
*** In fact, their stated goal is "To analyse canon and fanon depictions of the civilization of the Time Lords, in hopes of selectively reconstructing it in a way that is practical for life on earth."
** El Sandifer (author and blogger on ''TARDIS Eruditorum'') makes a large number of entertaining interpretations in her blog.
*** She likes to theorize that the Doctor is a wanted escapee from ''fiction'' itself. This is based primarily on Creator/PatrickTroughton's era, particularly "The Mind Robber", so it isn't brought up too often; however it does shine an amusing light on the Daleks, who are bent on a HostileShowTakeover and continually crashing preexisting shows (and sometimes rival network TV shows -- see ''Series/BigBrother''), which is why every Dalek 'reveal' is treated as a twist/cliffhanger: they keep trying to wreck the show. On the other hand, were it not for the story "The Daleks", the show would not have survived very long; This explains the Doctor's hesitance to prevent their creation in "Genesis of the Daleks", as doing so would erase him as well. Similarly, when the Daleks pop up in Totter's Lane [[{{Recap/DoctorWhoS25E1RemembranceOfTheDaleks}} at a chronological point before the show's premiere]], they are trying to stop ''Doctor Who'' from ever going to air.
*** Here's a brain-frier for you: "An Unearthly Child" aired one day after John F. Kennedy's shooting in Dallas. "The Deadly Assassin" is a riff of the JFK assassination. Tom Baker is Oswald. The real svengali behind the shooting is The Master. Therefore, the Master is recreating the conditions of ''Doctor Who''[='=]s premiere in order to take control of the show. (Yes, El really postulated this.)
*** The Doctor (and most notably, the Second Doctor) is defined by his habit of bringing the world down around your ears, then vanishing prior to rebuilding. By that logic, when the Second Doctor reappears in "The Two Doctors," he exposes the flaws in the show's infrastructure and then splits, causing it to be canceled.
*** Perhaps her biggest challenge was trying to make sense of the "Trial of a Time Lord" arc (aka "[[WaxingLyrical Fucking Valeyards, How Do They Work?]]") She guessed that the trial is unfolding during the Time War (occurring as it does on or near a future Gallifrey where the Doctor has not yet met Mel), and that the Doctor is actually on trial for committing genocide on the Time Lords in the upcoming series reboot, ''not'' the Vervoids as his prosecutors claim. The Valeyard is not merely an evil Doctor from a possible future, but an incarnation brainwashed by the Time Lords and obsessed with laws, unlike the troublesome maverick we know.
*** Additionally, El has shared her headcanon (on her Tumblr, not on the blog proper) that "The Chase" is another intrusion of the Time War, this time on the Hartnell era.
*** The famous "[[ScifiWritersHaveNoSenseOfScale constellation]] of Kasterborous" flub is the result of the Time Lords mapping their astronomy according to how ''Earth'' views their planet. This rapidly led to EpilepticTrees regarding humans being the top-secret {{precursors}} to the Time Lords. Wibbly wobbly, timey wimey, et cetera. [[note]]{{Jossed}} as of "The Beast Below".[[/note]]
*** Why did Gallifreyan history change between "The Three Doctors" and "The Deadly Assassin"? Because all that stuff about Rassilon and the Eye of Harmony ''was'' the events of "The Three Doctors"!
** All of the Sontarans were cloned from a single individual, and this individual was named General Sontar. It's important to note that this is ''still'' fanon, even though it's appeared in ExpandedUniverse works.
** In ''The End of Time,'' Rassilon orders that two Time Lords cover their eyes "like the Weeping Angels of old." This has led to fans thinking that the Time Lords somehow evolved into the Weeping Angels, despite the fact that there is ''no'' evidence of this whatsoever (and the Weeping Angels are stated to be very nearly as old as the universe, so presumably quite a bit older than the "billion years of Time Lord history" Rassilon mentions in ''The End of Time'').
** The decision in the 2005-present revival to introduce romance with regards to the Doctor went against the fanon that the Doctor was asexual or incapable of being aroused by females; that fanon stemmed primarily from a line of dialogue in 1979's "City of Death" in which the Doctor says to a female villain who is trying to distract him with sexiness, "you're a beautiful woman, probably" and the lack of explicit romance throughout the classic series. Ignoring the fact he referred to his own companion, Romana, as being attractive a season earlier. The GenderSwap of the Doctor further inflamed this debate as it was seen as playing into the fanon notion of Time Lords being asexual and genderless.
** After "The Timeless Children", a lot of fans believe that [[spoiler:Tecteun later changed their name to Rassilon]].
*** Although after the script for "The Timeless Children" was released, most people think Tecteun is actually The Other, not Rassilon.
** The idea that the Timeless Child is TheChosenOne or similar, [[spoiler:and therefore so is the Doctor]], mostly coming from those that dislike the idea. Nothing on-screen says anything about the Child being singled out in that way - they're special in that they're the only one of their kind known, and the origin of the Time Lords' ability to regenerate, not in their having been chosen for something. Relatedly, there's the idea that the Child is Rassilon's peer; that may be true in terms of the era they come from, but there's nothing on-screen regarding how they'd measure themselves against each other, [[spoiler:or even if Rassilon knows the Doctor is the Timeless Child]].
* ''Series/DowntonAbbey'':
** A recurring theory is that Edith is actually Rosamund's illegitimate daughter given to the Crawleys, explaining why Edith noticeably stands out from the rest of the family and is closer to Rosamund than to her own parents.
** It's generally accepted that Mrs. Hughes' full first name is "Elspeth", although this has never been confirmed.
* ''Series/DueSouth'':
** Based on information from the series finale, fanon usually has Ray Vecchio marrying Stella Kowalski, but the transcript of the last episode only says the two moved to Florida together - nothing about marriage.
** And it's popular in fanon for Fraser and Ray Kowalski to both live in Canada permanently after the end of the series, but nothing in the series finale says that either one stayed there after their adventure.
** The majority in fanon say that Fraser and Ray Kowalski are both gay. But nothing on the show points to this, since Fraser and both Rays are attracted to women, and both Rays were married.
*** Also a big fanon misconception is that Paul Gross was aware of slash, and so deliberately inserted "slashy scenes" into the last two seasons. But an interview he had just before the third season started (and after a number of episodes had probably been filmed) shows that he didn't know anything about slash until the interviewer brought it up, and he's never stated publicly that he added "slashy scenes."
** It's also strictly fanon that the Rays hate each other and never become friends. They were barely together in the series finale - not long enough to form a friendship - but they showed respect for each other after one small fight. If the series had continued, they would have probably become friends. There's no reason for them not to try to be friends for Fraser's sake - and it is canon that Fraser wants them to like each other.
** The big-name fans say Ray Vecchio is older than Fraser and Kowalski, and sometimes that Fraser is older than Kowalski. Nothing on the show indicates that. All three were probably intended to be the same age especially since ''[[spoiler: Ray Kowalski could not be that much younger than Ray Vecchio if he must be undercover as Vecchio]]''.
** It's also strictly fanon that Fraser hates "Benny," [=RayV's=] nickname for him. Nothing in canon indicates that Fraser hates it, or is even midlly annoyed by it.
** Ray Vecchio's time spent undercover is often fanon. He distinctly says that he was undercover for a "full year." Fanon has his undercover job lasting much longer, especially F/K slash. Probably because the shippers want to give Fraser time to form a closer relationship with [=RayK=] than the one he had with [=RayV=], but that's also fanon. Fraser was closer to [=RayV=] in canon.
* ''{{Series/Emergency}}'' did not delve deeply into character backgrounds, in typical Jack Webb fashion. However, there is a lot of fanon that has been formed:
** Gage's parents died when he was young (actually borrowed from another Randolph Mantooth character)
** Either Gage's parents or relatives abused him (hypothesized from certain behaviors he shows)
** He is half Native American (He only stated his native heritage-the half is from Randolph Mantooth's real heritage.)
** He was picked on for being mixed race (comes from what tends to get portrayed about reservation life,even if it isn't always totally true)
** He is Cheyenne or Lakota- comes from his mentioning growing up in Montana,where those tribes are dominant.
** John is often shown having horses, since he seems to have bought a ranch in one episode, and is known to like to ride, even if he hadn't done it in so long before "Saddled" that he couldn't walk the next day.
** Roy's daughter is always called Jennifer. Her name was never mentioned,but Kevin Tighe has a daughter named Jennifer,and it was borrowed. She is frequently called "Jenny Bean" by John.
** Roy and Chet were both in Vietnam. We are told they are Army vets, and it makes sense given the time period and character ages.
** Captain Stanley's wife is usually called Emily or Elly. They end up with a couple kids despite none being mentioned.
** Brice is usually paired with Bellingham when he appears, even though Bellingham was only mentioned as partnering temporarily with Brice while Roy and John were both injured.
** Many fans assume Chet Kelly died in the line of duty sometime before the last film, due to a line in the film. However, it is not said definitely.
* ''Series/{{Firefly}}'':
** Many fanfics have River referring to herself exclusively in the third person. This only occurred on two occasions in canon, one of which was in sarcasm.
** The fans are adamant that Book was a former Operative, to the point of decrying ''The Shepherd's Tale'' which says otherwise, and many people considering it [[FanonDiscontinuity non-canon]].
** Likewise, the belief that River's parents knew what the Academy was and had been either paid or coerced into sending her there, possibly even having conceived her solely for that purpose, is fairly widespread. This is implied in the episode "Safe", where River is shown to be TheUnfavorite and they brush off Simon as imagining things when he shows them her coded letters, but it's never directly stated and it's possible they really did believe nothing was wrong, or else realized Simon was right but were too afraid of losing their money and status to do anything about it.
** A common fan theory is that Zoe refused to got out with Wash until he shaved his mustache, or that she made shaving it a condition of further dating/marriage. One of the novels seems to confirm it.
** There's a persistent fanon that Inara would lose her Companion license if she began an ongoing unpaid sexual relationship with Mal, although fanon differs as to whether this is because Companions aren't allowed to have unpaid relationships with '''anyone''', or if it's specifically because of Mal's disreputable character. There's nothing in canon to support either idea. She did get together with Mal for a while in the comics, but it was during the period where she was kicked out of the guild. When she was shown as a priestess later, they had long since broke up.
** Before Zoe was shown to be pregnant in the comics, there was a theory going around that Wash might’ve been sterile due to growing up on a heavily polluted world. The revelation he traveled a lot with his dad may explain why he wasn’t.
* ''Series/{{Friends}}'':
** Ross and Rachel hook up in the last episode but they ''don't'' end up married. However many fans and shippers like to think that they are now HappilyMarried (or better, remarried). Even the show's official wiki lists Rachel as Ross's current wife.
** Many fans believe Monica's middle initial 'E' stands for Elizabeth.
** Another popular theory is that Monica and Chandler, who adopted twins at the end of the show, later managed to have a child naturally. (It was 'unlikely' not 'impossible'). Although their adoption storyline was popular fans found it hard to see the one committed couple who had worked so hard for a family struggle with infertility so this is a reassuring comfort. It also matches Monica's mother who was thought to be barren before having her and Ross. Bonus points if the kid's called Daniel which was what Monica originally wanted to call her first son.
** Despite how hated the spin-off' 'Series/{{Joey}}'' was a lot of fans like to think he married Alex who was his LoveInterest from the show so he could also have happy ending. (And of course he moved back to New York to be with the Friends again).
** Fans also try to shoehorn the opening credits sequence of the six friends dancing in the fountain with the couch, lamp, and lights strung up everywhere as canon by saying it was a photo shoot that Joey did early on in his career, and when they needed a handful of good-looking people on short notice, Joey called the others.
* On ''Series/GilmoreGirls'', the character Tristin repeatedly called Rory "Mary" as a nod to her innocent appearance and actions. In fanon, Rory and other characters often call Tristin "Bible Boy" though it was never spoken on-screen.
** A popular theory is that after the series, when Rory was on campaign trail, she stopped in Philly to see Jess. Whether a platonic or romantic meeting, its a staple of most 'After Season 7'' fanfics.
** Luke's mother was an older version of [[GenkiGirl Lorelai]]. Because [[GenerationXerox Luke is like his Dad.]]
* ''Series/{{Glee}}'' is one of the few shows where "This episode sucks because it violates canon!" ''could'' be a valid complaint, since the show is infamous among the fandom and critics alike for its on-again, off-again relationship with continuity. That said, it doesn't keep the fans from coming up with stuff that was ''never'' revealed in canon:
** Strangely common in fanfic is the idea that [[AlphaBitch Quinn]] [[FallenPrincess Fabray]] is a brilliant pianist. Occasionally added is the idea that her parents sold her beloved piano after she became a Cheerio.
** Kurt and Puck adore ''Literature/{{Harry Potter}}''. If one of them only shows up in a fic once, it will be to agree with the other one that HP is [[Theatre/AVeryPotterMusical totally awesome]]. Blaine, as well. [[Creator/DarrenCriss For very]] [[Theatre/AVeryPotterMusical obvious reasons]].
** Warblers Wes and David are more or less crazy. Sometimes, they are also utter failures when it comes to matchmaking.
** Up until Kurt [[{{Jossed}} mentioned]] in ''The Sue Sylvester Bowl Shuffle'' that he still lived at home, the fandom generally assumed that Dalton Academy was a boarding school.
** The name of Puck's little sister is as of yet [[NoNameGiven unknown]], but lots and lots of fanfic writers call her Sarah. All the others call her Hannah.
** At the end of the only episode Kurt's car has shown up in, Kurt tells Mercedes that his dad took it away from him. That was almost two seasons ago, and the car hasn't even been mentioned since then. Still, there are ''very'' few, if any, Kurt-centered fanfics in which he doesn't have his car. How else would he get to Westerville and back? If someone else was dropping him off and picking him up, s/he would have to drive an hour and a half each way, making two trips. Six hours of driving each day.
** Two about Dave Karofsky: he's a math nerd/whiz (from his father mentioning he was an A and B student, and his taking Calculus even as a high school junior) and he's a terrific singer (from Will's compliment in Sue Sylvester Shuffle and the fact that Creator/MaxAdler is the only actor who plays a student who's actually been in a real glee club).
*** Dave is also almost always an only child and quite commonly, his mother is dead/gone (which is almost certainly based on the fact that during the two meetings with the principal and Kurt and Dave's families in {{Canon}}, only Dave's father has been there and there is never any mention of a mother.)
*** He mentions his mother in "On My Way". She may have been working at the time.
** Carole is a nurse, and Kurt's mother's name is Elizabeth
** If Blaine's aspirations are brought up in a fic, they'll almost invariably center around law, medicine or teaching.
** Many fans believe that the reason Blaine is in the year below Kurt isn't actually that he's a year younger than him. Their theory is that when Blaine was attacked after the Sadie Hawkins dance that he mentions briefly at one point, he sustained injuries that were severe enough that he had to [[HeldBackInSchool repeat a year]].
** Matt and Mike are usually best friends, even though there is nothing to support this. Even calling them ThoseTwoGuys is pushing it because they don't much together
** The character of Sugar is, in the eyes of many a Gleek, the daughter of Brittany and Santana, who went back in time to make sure her parents got together. Doubles as slightly AscendedFanon, as Creator/HeatherMorris, Creator/NayaRivera, and Sugar's portrayer Vanessa Lengies heard about this theory and ran with it, having scenes with subtle nods to the fanon.
*** Variations also exist with the Season 3 character Rory being Klaine's son (and using the accent to avoid suspicion), and the character of Harmony, usually revealed to be Faberry's daughter.
** Sam's middle name is often Dwight after his father, even though there is no evidence to support such.
* ''Series/GreysAnatomy'' fanfics in which George survives invariably have him specialize in trauma surgery, thanks to a one-off line from Owen that he should. Lexie is quite often a plastics fellow, probably because her two most significant love interests both went into plastics.
* ''Series/H2OJustAddWater'' and ''Series/MakoMermaidsAnH2OAdventure'':
** Thanks to ContinuityDrift, several theories popped up trying to reconcile the differences in mermaid lore seen in both shows.
*** The Mako Pod was absent during the plot of ''H₂O'', and during the time when Ms. Chatham and her friends were mermaids. They only returned after the girls left or were {{depower}}ed, never knowing that three land girls gained mermaid powers while they were gone.
*** The Moon Pool was rebuilt and remodeled by the Mako Pod after it was devastated by Ryan and Sophie in the final episodes of ''H₂O''. Inexplicably, Rikki comments that the Moon Pool hasn't changed since she left in the final episode of ''Mako Mermaids'', despite the obvious differences.
*** Every merperson in ''Mako Mermaids'' has a diverse range of magical abilities, in contrast to the ones in ''H₂O'' only having unique abilities. This lead to the theory that mermaid powers beyond the ones natural to the girls can be learned. [[AnIcePerson Emma]], [[MakingASplash Cleo]], [[PlayingWithFire Rikki]], and [[{{Transmutation}} Bella]] simply never thought of trying to learn each other's powers, while [[AllYourPowersCombined Charlotte]] learned all of the former three's powers thanks to sheer determination, not by being in the Moon Pool by herself as was theorized in-universe. Supporting this is Rikki clumsily using hydrokinesis and asking Weilan to teach her invisibility in the final episode of ''Mako Mermaids''.
** Mitch from ''H₂O'' and Dr. Ross from ''Mako Mermaids'' are played by the same actor, and thus are agreed to be the same person by the fandom.
* ''Series/{{Heroes}}'' has accumulated quite a bit of fanon. Popular theories include:
** Sylar has superhuman endurance, and also the {{Jossed}} idea that he eats brains.
** Lyle is adopted.
*** Confirmed in a deleted scene from the first season meaning it may or may not still be canon. The on-line comics also mention that HRG and Sandra could not conceive a child.
** Adam is the ancestor of most, if not all, of the Heroes.
** Mohinder went to boarding school or to university in England, hence the accent. It's also common fanon that his native language is Tamil (which makes sense, since this is the primary language spoken in Chennai, where he grew up) and that he is an atheist (arguably implied in the comic "Monsters", but contradicted at several points on the show) and a vegetarian (this one has some support; the Heroes Wiki notes that the religious symbols at Chandra's funeral imply that he is a [[http://en.wikipedia.org/wiki/Vaishnava Vaishnava]] Hindu of the [[http://en.wikipedia.org/wiki/Sri%20Sampradaya Sri Sampradaya]] sect, and most of them are [traditionally vegetarian] Brahmins).
** Nathan is eleven years older than Peter (his exact age is unknown, but presumably he's at least 35 in the "Five Years Gone" alternate future to make him legally eligible for the U.S. Presidency; Peter is stated to be 26 as of Volume 1).
** Mohinder's unnamed mother tends to be called Anjali in fics.
** Sylar's original ability of knowing how things (such as watches) work has the side-effect of allowing him to always know the exact time.
** Claude is either bisexual or completely gay, along with [[HoYay the rest of the male characters]]. Some people think he named his pigeons.
** Elle is the mother of Sylar/Gabriel's son Noah in the future. While it's widely recognized that it's not ''technically'' canon, few realize it's not even hinted or implied.
*** Making [[FanNickname Kid Noah]] a biological descendant of either (but especially both) creates not only time line, but casting problems. The actor appeared to be about five to eight years of age when Knox [[spoiler:kills him]]. Yet, if the Exposed Future is four years after the Volume 3 Present, then how did Kid Noah grow from an embryo to a very-mature three-year-old in that little time period? [[CanonDisContinuity Then again...]]
** Elle is also often given a fear of water. It is shown as a weakness of hers, but she's never stated to outright be afraid of it.
* About half of the episodes of ''Series/{{Highlander}}'' are set in an unnamed city in the Pacific Northwest. Fans unanimously referred to this city as "Seacouver" (a portmanteau of "Seattle" and "Vancouver") but this was never explicitly stated on the show itself. The "Watcher CD" given away with VHS box sets (and, later, the DVD extras) finally made this name official.
** Methos, a 5,000 year old Immortal, was shown for his first few appearances on the show as a somewhat hapless, normal kind of man who just happened to be really old. However, at some point the writers must have caught on to the fact the [[{{Fanon}} characterization was incongruous based on his canon age and probable life experiences]], because several episodes in Season Five established him as having a dark past. Fans ran with this interpretation, often [[FixFic ret-conning]] Methos’ earlier actions and behaviors to make him a far more complex, morally ambiguous and - arguably - [[GuileHero interesting]] character than was initially supported by his actions in Seasons Three and Four. It’s also basically [[{{Fanon}} fanon]] at this point that Methos is bisexual. Most [[FanFic fanfiction]] about Methos involves at least some elements of this [[BloodierAndGorier interpretation]] of the character.
* In the mini-series adaptation ''Series/HoratioHornblower'', Archie Kennedy was mostly an AscendedExtra and a CompositeCharacter. In the books, there was a midshipman named Kennedy, appearing in one scene, and there was a sailor who had a fit during a stealth raid. Those are the only elements from the book canon that were used to create Archie. He also became a midshipman particularly tormented by Simpson (in the book, Hornblower was the youngest and suffered the most) and Archie was given lines of other characters.[[note]]In "The Frogs and the Lobsters", he has Lt. Bracegirdle's speech about civil war, and in "Mutiny", he was kind to the beaten middie Wellard, which belongs to Lt. Bush.[[/note]] In the series, not much about his background is known, but some facts are intriguing. Lots of the fan fic stories focus on Archie's days spent at theatre, because he said that he once knew Drury Lane as if it was his home. He also seems to love Creator/WilliamShakespeare since he quoted or paraphrased him several times. In fics, he's a total {{Bookworm}} who knows his Shakespeare really well to the point of obsession. Creator/JamieBamber, his actor, said in interviews that he thought that Archie was a third son of Scottish lord, and fans have embraced this idea as well, and it fits because Kennedy is a Scottish surname and the name Archibald was a particularly popular given name among Scottish nobility. His aristocratic family also tends to be pretty screwed up and distant. Many also presume Simpson's tormenting of Archie included sexual abuse (while there's some subtext that implies it, it's never been explicitly stated to be true).
* ''Series/{{House}}'':
** When it's not "Wilson's cancer goes into remission, they become a couple for real and live HappilyEverAfter", most people assume that House killed himself after Wilson died because, considering what he's like, he ''would'' probably choose a last self destruct binge rather than jail or hiding out alone forever. Hugh Laurie supports it too, saying in one interview he doesn't see House intending to live long after Wilson goes.
** While the possibility is dismissed within one episode, autistic fans still accept House as one of their own with all the relatable always having something in his hands to help him think, wanting to turn his humanity off and the ValuesResonance speech about privileged white neurotypicals wanting to break marginalized people into being more like them.
* ''Series/HouseOfAnubis'':
** It is generally accepted that Patricia, Jerome and Alfie used to be best friends, and some even think Jerome and Patricia dated. However, nothing confirms this, and the most evidence is that the trio hung out a lot in the premier.
** Patricia is TheUnfavorite of her family and Piper gets all the attention. It has some basis due to a throwaway line about Patricia wanting attention and how Piper is the more talented and nicer of the two twins, but it has never been confirmed.
** Another popular idea is that Fabian's parents could be [[AbusiveParents abusive]]. This is partially due to his shy, ExtremeDoormat personality and the fact that his parents have never been mentioned in canon. The only family members he does have on the show are an uncle and a godfather, neither of which is seen on a consistent basis, which also makes fans curious about what's going on in his family.
* ''Series/{{iCarly}}'':
** Parts of the fandom are quite convinced that Carly and Sam are lesbians based on many moments between the two. At minimum, Sam is often seen as bisexual, even by some Freddie/Sam fans.
** There is also Wendy, who is a recurring MrExposition on the show, being blown up into the Seattle version of ''Series/GossipGirl''.
** Sam as being [[CulturallyReligious non-practicing]] or secular Jewish was a common piece of fanon. The show itself eventually had her outright say that she wasn't Jewish.
** Sam's canonically emotionally abusive mother Pam is a [[AbusiveParents physically abusive]] AlcoholicParent (and sometimes a JunkieParent as well). She also treats Sam as TheUnfavorite.
* ''Franchise/KamenRider'':
** ''Series/KamenRiderBlackRX'': The Crisis Emperor is the Great Leader of Shocker. This is somewhat supported by canon, due to all of the Great Leader's official incarnations being voiced by Goro Naya until the man's death, and the Crisis Emperor is a shape-shifting eldritch abomination like all of the Great Leader's other forms.
** ''Series/KamenRiderDecade'': Perpetual pain-in-the-ass Narutaki gets a lot of fanon because there's extremely little canon information for him (he has dimensional powers and hates Tsukasa with a passion) and it seems unlikely that Toei will ever fulfill their promise of releasing a ''Decade'' movie that explains his backstory. One popular theory is that, like the Crisis Emperor mentioned above, he's some incarnation of the Great Leader and an EvilCounterpart to Decade, since in the movies he's taken on the forms of past ''Rider'' enemies like Colonel Zol and Kani Laser. However, this clashes with his appearance in ''Series/KamenRiderGaim'', where he tells Kouta that he's "an ally of all Riders" and is seemingly friends with the Conductor from ''Series/ResshaSentaiToqger''. The mystery continues.
*** The ''Decade'' novel says that Narutaki is a vampiric being who [[WasOnceAMan whose sanity and humanity degraded]] as he hopped dimensions and wants to destroy the Rider multiverse so he could create his own ideal world. However, this novel is generally [[FanonDiscontinuity ignored by the fandom]] because of the low quality of the writing and how it gets even basic facts about the franchise wrong.
** ''Series/KamenRiderDouble'': Shotaro was a petty criminal in the past. This is based on a flashback in one of the Jewel Dopant episodes to him running from Jinno when Jinno was a beat cop.
*** [[Series/KamenRiderRyuki Ren Akiyama]] is the father of the little girl featured in episodes 5-6, because the doll her father gave her resembles Kamen Rider Knight.
** ''Series/KamenRiderKuuga'': Yuusuke Godai is dead. Possibly a theory to explain his absence from ''Series/KamenRiderDecade'', where the Riders who appeared in the movies were all implied to be the originals, except for Kuuga, replaced by his AU counterpart Yuusuke Onodera.
*** Godai is confirmed to still be alive, but missing, in a spin-off novel - although CanonDiscontinuity means he could still be dead in the TV/film universe.
*** Word of God has stated that Godai is the Kuuga that appears in the Wizard finale episodes, thus has further been debunked. More than likely inserted as a result of the fandoms writhing Hatred of Yuusuke Onodera.
** ''Series/KamenRiderOOO'': Chiyoko Shiraishi is related to Mako Shiraishi from ''Series/SamuraiSentaiShinkenger'', or (since ''Decade'' states that the Shinkengers' world has never had a Kamen Rider) is some kind of AU counterpart to Mako or her family. Both OOO and Shinkenger were written by Yasuko Kobayashi.
** ''Series/KamenRiderFourze'': Sonoda, Kijima and Sugiura were never rescued from M-Bus, and just forgotten or left there to die. Again contradicted in a spin-off novel which states they were rescued and Sonoda inspired Gentaro's decision to become a teacher in ''Movie Wars Ultimatum''; but the novel may not be considered on-screen canon.
*** It has in fact been word-of-godded to have occurred.
** ''Series/KamenRiderGaim'': Ryoji Hase has an older brother named Ryoichi. Became popular with fans after the actor suggested this in an interview.
** ''Series/KamenRiderGeats'': Since Lopo was never given a Buckle she matched with, a lot of fans have decided her match is the Boost Buckle. This is because it's the only regular Buckle she uses that isn't Zombie (Michinaga's), and it fits her character since it is focused on speed a lot of the time. It helps that she used it to gain superspeed, something even Ace wasn't able to do, and the Summer movie had her use it alongside everyone else using their main Buckle.
* ''Series/LawAndOrder'':
** Serena Southerlyn is every subsequent female lawyer's fabulously bitter/[[DeadpanSnarker sarcastic]]/[[ReallyGetsAround promiscuous]] best friend. Particularly prominent in [[Series/LawAndOrderSpecialVictimsUnit SVU]] Alex/Olivia fics, it must be said, proving the age-old trope that beautiful blonde ADA BirdsOfAFeather will be stuck together in fanfiction.
** Abbie Carmichael seems to be gay in a terrifying number of fics, considering how [[BlondeRepublicanSexKitten conservative]] she was, and the fate of her successor (you sort of don't care if she's paired with Olivia Benson).
** Based off a line by Goren in an episode of ''Series/LawAndOrderCriminalIntent'' than Van Buren had tried repeatedly to get him back from Staten Island, the "detective, first-grade" she was going to replace Fontana with when she got stuck with [[EnsignNewbie Detective Cassady]] was going to be Mike Logan.
* ''Series/LawAndOrderSpecialVictimsUnit'':
** Despite the fact that we've only seen them dating men, Olivia and Alex on ''Law & Order: SVU'' are claimed as lesbians by the show's large lesbian fanbase. Some of these fans were outraged when, in the episode "Ghost", Alex told Olivia about the man she'd been seeing. The term "manvil" was coined to describe the show supposedly [[{{Anvilicious}} dropping anvils]] that Alex likes men. Said accusation [[NoBisexuals neatly ignores the possibility of bisexuality]], but as always {{Subtext}} is where you find it. And of course, it wasn't nearly so bad as Serena Southerlyn's [[AssPull last minute coming out]]. WordOfGod declared that there was, in fact, [[UnresolvedSexualTension UST]] between the two women. The actress who plays Alex basically admitted that something was going on:
--->'''Stephanie March''': I'm not saying we're not... I'm not saying we're not in love.
** Another common piece of fanon pertaining to Alex Cabot is that Liz Donnelly is her godmother/stepmother/aunt.
** George and Alex being best friends and bonding over their LGBT identities is common in A/O fics as well
** The overwhelming majority of the fandom has concluded that Rafael Barba is bisexual (helped along by the fact that his actor, Raul Esparza, is openly bisexual in real life).
** Fin calling Olivia "baby girl".
** Elizabeth Stabler is called "Lizzie" by the fandom so often that most of the fans have forgotten that she is actually never referred to by this name even once.
** Kathy Stabler is often assumed to be a nurse even though where she works is never directly stated.
** George is usually written having a strained relationship with his family, based on him being gay and a line during a season three episode mentioning that his family was strictly traditional.
** Rafael having gone to Harvard on scholarship was accepted by fans quite a while before it was confirmed onscreen.
* ''Series/LazyTown'':
** It's fairly common to give villain Robbie Rotten some sort of magical heritage to go with Sportacus's somewhat implied elven heritage. [[note]]While in the original plays the character that would become Sportacus is explicitly referred to as an elf, Sportacus's race is [[AmbiguouslyHuman more ambiguous]].[[/note]] The usual choice is to make Robbie at least part [[TheFairFolk fae]].
** It's also fairly common to make the original incarnations of Sportacus and Robbie Rotten - Íþróttaálfurinn and Glanni Glæpur respectively - relatives of some sort to their more well known incarnations-brother, father, cousin, and uncle have all been used at some point.
** Fan''artists'', meanwhile, have collectively decided that under that hat of his Sportacus has curly/wavy blond hair (not too unlike series creator and first Sportacus actor Magnús Scheving's) - this ''despite'' the fact that based on the little hair that's seen, ''and'' WordOfGod, he's a brunette.
** There are two fan explanations for why sugar makes Sportacus lethargic. One is that he's diabetic, the other is that all members of his species (whatever species he is) reacts that way to sugar.
* Fanon for ''Series/TheLoneGunmen'' (and by extension, its parent show ''Series/TheXFiles'') can be traced back to a handful of very old fanfics. These include: the idea that Langley used to be addicted to drugs, and giving him the nickname "Ree," the speculation that Frohike had served in Vietnam as a sniper, and that Byers was a widower. Another fanon element [[FanonDiscontinuity defiantly ignores]] the aptly-named episode "Jump The Shark" to state that [[UnreliableNarrator Fletcher]] was lying through his teeth (with the Gunmen's strangely OOC behavior being offered up as "proof") and/or that the Gunmen faked their deaths. According to the Season 10 continuation comic, [[spoiler:the latter]], but according to the 2016 miniseries, [[spoiler:they're dead]].
* ''Series/{{Lost}}'' fanon is mainly theories that become so widely accepted that they're taken as canon. Of course, this is generally because of ''massive'' hints:
** Jacob's nemesis being the Smoke Monster, and Richard being first mate of the Black Rock are all common. Season Six tells us yes and no, but close on those two (Richard was actually a ''prisoner'' on board the Black Rock).
** Some fans have taken to calling the Smoke Monster Esau, after biblical Jacob's older brother.
*** As per his original casting call (and confirmed later by Kristin Dos Santos), his name is meant to be Samuel, although this is never properly stated.
* ''{{Series/MASH}}'':
** Ever since MASH fic author onekisstotakewithme gave her that second name, Peg Hunnicutt has been Peggy Jane for the fandom, to the point many people don't remember where it came from.
** Continuity errors and retcons regarding Hawkeye's family (early seasons had him say he had a sister and his mother was still alive, while later seasons had him claim he was an only child and his father was a widower) are typically chalked up to brain misfires on his part, considering his later canon TraumaInducedAmnesia and implied AmbiguousDisorder.
** Then there's the 'Hawkeye is bisexual' fanon that enables a significant portion of slash fic.
* ''{{Series/Merlin|2008}}'':
** Fans generally assume that Gwen's mother is dead (often she is said to have died in childbirth, to parallel Ygraine) and that Merlin was named for the [[http://en.wikipedia.org/wiki/Merlin_%28bird%29 falcon]]. They also sometimes use 'Ambrosius' and 'Myrddin Wyllt' as some of the 'many names' for Merlin mentioned by the Dragon. And whether Gaius being Merlin's uncle is this, Word of Actor (Creator/RichardWilson believes Hunith to be Gaius' sister) or WordOfGod is a matter of some confusion.
** Also, some fans say that Merlin is a warlock and not a sorcerer because he was born with his powers, and sorcerers have to learn magic. This is because Merlin is referred to as a warlock in the show, but all others are called sorcerers (some {{fanfiction}} has him angrily defending himself against accusations of being a sorcerer on these bounds). However, it's never addressed in the show, so we don't know if that's canon or not.
** The existence of 'real' Arthurian legend also provides a huge source for fanfics, such as Mordred being Morgause's son.
** It's often speculated that Morgana's father Gorlois was killed due to a UriahGambit organized by Uther. Thing is, the circumstances of Gorlois's death were described in season 1 (that he was sent into battle and Uther neglected to send him reinforcements). At the time, there was no reason to suspect Uther deliberately withheld them. By the time season 3 rolled around, the writers had decided to make Morgana Uther's biological daughter (after he had an affair with Gorlois's wife). The RetCon of Morgana's parentage throws a very different light on Gorlois's death, though it's never speculated on in the show itself.
* One bit of widely accepted ''Series/{{NCIS}}'' fanon is that Ziva was raped at some stage, most likely multiple times. Somalia is pretty much the epitome of Ziva going through hell.
** She was an attractive woman, tied up in an all-male camp of violent terrorists who enjoyed hurting and torturing her, and saw her as less than human. It's not exactly jumping far to get to that conclusion.
*** Especially since she still refuses to talk about it.
*** And Gibbs and Vance have had several conversations about how she went through more over there than anyone originally thought.
** Up until it was confirmed in season eight, it was very well accepted that Abby's father was dead, even though both of her parents are mentioned in present-tense in the pilot.
* ''Series/Numb3rs'':
** Even though it is never said in canon, Margaret was affectionately called "Maggie" by Alan.
* In ''Series/NYPDBlue'', although it isn't explicitly depicted, fans like to think that Kelly and Janice did end up together after he had to leave the police force and once she got out of jail, as he leaves the show only two episodes after she does and [[https://www.youtube.com/watch?v=3QNRwqQl9oA Janice's last scene]] had her theorizing that she would only be in for six months, with the implication that Kelly would visit her in the meantime.
* In ''Series/TheOC'', fans think Alex's ex-girlfriend Jodie is an emancipated minor and also a lesbian TheCasanova.
* ''Series/OddSquad'':
** {{Immortality}} is a frequent topic of discussion in the fandom. One common theory is that the agents' badge phones keep them immortal, but other canon tidbits (like Oprah being able to control her aging as the Big O) contradict it. Despite this, however, the badge phones keeping agents the same ages is an accepted fanon theory. Some of the more popular fanfics give agents ProportionalAging abilites that come from the badges.
** Before Otis was revealed to be [[spoiler:a former villain,]] the RunningGag throughout Season 2 of toast appearing at various points in various episodes was correlated to him, since ducks are known to eat bread crumbs.
** And speaking of toast, it was a common theory that toast was more than just a mere RunningGag and was going to play a big part in the Season 2 finale, which ended up being jossed.
** Big Red, one of the citizens of Ms. O's old town in "Fistful of Fruit Juice", is thought by fans to have grown up to become Santa Claus, hence why Ms. O calls him by Big Red in "Reindeer Games".
** There's quite a bit of fanon surrounding Odd Squad agents having InvisibleParents and living in their own houses, since the show deliberately doesn't elaborate on any character's home lives too much.
** For a time, some fans believed that Otis was a dog due to the Season 1 episode "Training Day", where another Otis, an Australian shepherd dog working as an Odd Squad agent, was briefly introduced. Similarly, Ohlm being a dog was fanon due to having similar behaviors (being easily distracted, doesn't answer questions when he's asked them, etc.) and turning himself into a puppy at the end of "And Then They Were Puppies".
** There was lots of fanon surrounding the true identity of The Shadow, the BigBad of the first half of Season 3, with theories ranging from her being a dropout of the Odd Squad Academy to her being related to Opal in some way.
** Orla is often seen as being a lesbian. This is somewhat supported by [[https://static.wikia.nocookie.net/oddsquad/images/9/9c/Orla_with_rainbow-itis_OT_S2E4.png/revision/latest?cb=20210904080114 this image]] from the ''WebVideo/{{OddTube}}'' episode "The Button Song" depicting Orla with "rainbow-itis" (which looks like the gay pride flag) as well as a scene from "Can You Wrangle It?" which shows Orla and Oswald in the bullpen lit with bisexual lighting. On a similar note, due to Oswald being in that scene, as well as in "Monumental Oddness" being the officiant of a wedding between two lesbian women, many tend to view him as being somewhere on the LGBTQ+ spectrum.
** There is an absolute ''metric-ton'' of fanon surrounding ''Odd Squad'' and the Website/SCPFoundation. The most commonly accepted one is that Odd Squad, as an organization, is a kid-friendly version of the SCP Foundation. Fanon about ''Odd Squad'' relating to shows like ''WesternAnimation/CodenameKidsNextDoor'' and ''[[Series/SquareOneTV Mathnet]]'' is also common.
** Due to his MellowFellow personality, Ocean is usually seen as being constantly high on marijuana.
* ''Series/OnceUponATime'':
** Emma and/or Regina being bisexual is a very common headcanon among the fandom, especially with both being big LauncherOfAThousandShips. In canon, both have only shown interest in male characters, but are at the center of a lot of HoYay.
** Mr. Gold's first name (if he has one) is never revealed, but it's not uncommon for "Robert Gold" to be used in fanworks, likely after [[Creator/RobertCarlyle his actor]]. Another common fanwork name is "Adam", after the (unofficial, unspoken, probably non-canon) name of the Prince in Disney's version of ''WesternAnimation/BeautyAndTheBeast'', from which the show takes a lot of cues.
** In a ''highly'' divided fandom, one thing almost everyone agrees on is that the Blue Fairy is evil or at least has some hidden agenda. These fans theorize that Blue could see the future much like Rumple when she gave Bae the bean, meaning she deliberately set in motion the events that led to the casting of the Dark Curse. She also broke up Dreamy and Nova, [[spoiler:turned August back into a child, preventing him from telling the town about Greg and Tamara]], kept Tinker Bell from helping Regina during her unhappy marriage, and most important of all, [[spoiler:banished Rumpelstiltskin's mother which causes ''everything'' in the series to follow]].
* ''Series/OrphanBlack'' has a multitude of open-ended questions, whether it has to do with plotlines or characters. This makes it a fairly popular show for fanons:
** Helena eats like an animal because, as a kid, she was hardly fed. This is supported by the abusive way she was trained and coaxed to kill the other clones by Tomas and the implied abuse that the nuns also made her endure.
* With 500+ significant characters in 17 seasons, ''Franchise/PowerRangers'' has a fairly hefty showing of this, to the point where some of the fanon actually conflicts with ''itself'', and not just canon. Rangerwiki, a PR Wiki, has a [[http://web.archive.org/web/20120327151238/http://www.rangerwiki.com:80/dokuwiki/doku.php?id=extra:fanon list]] of some of the more common instances of fanon.
** One notable example of ''PR'' fanon becoming canon happened in 2002: a long-time fan began writing for the show in its tenth season, and made multiple references to an older fandom-wide missing episode hoax in a pivotal episode, suddenly canonizing the hoax's storyline... though as [[WebVideo/AtopTheFourthWall Linkara]] [[WebVideo/HistoryOfPowerRangers points out]], it probably would have a) not explained everything and b) sucked.
** Some of the more popular bits of fanon are:
*** Billy's last name (he was never given one in-show, but the fans made it up, and when the official website was put together, they just [[ThrowItIn threw it in]]).
*** After the death of actress Thuy Trang in 2001, the fandom has generally agreed that her character Trini Kwan [[TheCharacterDiedWithHim passed away as well]]. ''Film/MightyMorphinPowerRangersOnceAndAlways'' would end up [[AscendedFanon having a death scene for Trini]].
*** Z Delgado of SPD is the daughter of Danny Delgado of Wild Force.
*** One bit of fanon acknowledged by the creators is the idea that ''Operation Overdrive'''s Mack was created as a SexBot, to explain why Hartford would create a robotic "son" that's already an adult (or at least almost). According to WordOfGod, concerns were raised about this during the show's production, but dismissed because Bruce Kalish didn't think anyone would be warped enough to reach that conclusion. He was wrong.
*** Some fans have theorized that Jason and Kim were in a relationship during ''[[Series/PowerRangersTurbo Turbo: A Power Rangers Movie]]''. Some even go further and speculate that Jason was the other guy mentioned in the infamous DearJohnLetter from ''[[Series/PowerRangersZeo Zeo]]''.
** Somewhere between fanon, ActorAllusion and fandom inside-joke is the idea that Taylor (from Series/PowerRangersWildForce) and Tommy (from... well, everything) hooked up. This is because their actors were in a sex scene together on the MTV show ''Undressed''.
** The organization of evil forces seen in ''Series/PowerRangersInSpace'' is never referred to in that series as the "United Alliance of Evil". That name comes from a throwaway line in ''Series/PowerRangersZeo''.
** Fan-speculation abounded for literally two decades when some noticed that the episodes in late season 1 had no Zyuranger counterparts and the obvious Dairanger/Zyuranger splicing in early season 2. These extra episodes produced by Toei were called [=Zyu2=] by fans. There's been tons of speculation about them since, some of which has been confirmed, some of which has been {{Jossed}} by stunt coordinator Jeff Pruitt posting some [=Zyu2=] footage on his Website/YouTube channel. Here's a basic rundown of the big ones.
*** Many of the monsters thought to be killed by the Power Blaster had zord battles (confirmed)
*** One monster was aided by Lokar (Jossed)
*** One monster battled the Dragonzord Battle Mode and couldn't be used for that reason (Jossed)
*** The effect on the monster in the Thunderzord battles indicate its death (confirmed), meaning superimposed explosion for Ultrazord, slash for Megazord.
** The idea that the "K.O." acronym in [[Series/PowerRangersInSpace KO-35]] stands for "Karovan Outpost", and that it's just one part of a larger "Karovan Empire". In-show, Andros always just called himself "human" (with the HandWave that "Earth isn't the only planet where humans live"), and it was never made clear if KO-35 was his people's planet of origin.
** Although he did say he was from 'a space colony' in his introduction episode.
** A theory put in the comments of WebVideo/HistoryOfPowerRangers that explains the plotholes concerning Thrax from ''Series/PowerRangersOperationOverdrive'' is that he was a two-bit conman. Thrax wasn't his real name; to build himself up he pretended to be a villain the Sentinel Knight fought and then claimed to be Rita and Zedd's son. He doesn't have the strength to fight the Rangers and thus cons the other villains into doing it for him.
** Due to their actors being brothers, some fans think that the ''Ninja Steel'' Blue Ranger is a descendant of ''Dino Charge'' Koda's younger brother.
* ''Series/TheProfessionals'':
** The reason the sets are always different for Bodie and Doyle's respective flats every time we see them is that [=CI5=] maintains a number of flats which it's agents live in, and they move their agents around regularly.
** Doyle is moody, inclined to tears, and a vegetarian.
** Bodie is a cold-blooded loner, had a terrible childood, had a hellish experience being a mercenary in Africa, was rescued from it by Cowley and therefore looks up to Cowley as a father figure. [[DependingOnTheWriter Depending on who's writing]] the fic, he may well have been raped during all this suffering. All of which is only based on the canonical facts that he left school at 14 and was later a mercenary for some time.
** And they are both [[HoYay at it like ferrets, of course.]]
* ''Series/TheShield'' has Ronnie Gardocki, an AscendedExtra character who was the subject to much fanon as far as fans of the character grafting onto him a personality of Ronnie being a geeky cop who fell in with the bad crowd that was the Strike Team, as opposed to be being inherently corrupt. While the show and actor David Rees Snell largely embraced this fandom-based viewpoint towards the character (indeed, a plot point in the season seven premier was based around the notion of Ronnie having never killed a man in cold blood until that episode), it didn't stop the actor from acknowledging [[DracoInLeatherPants how his fans often downplayed his character's willingness to do bad things]], [[MisaimedFandom pointing out that Ronnie had to been somewhat evil in order to have been recruited into the Strike Team]].
* Most members of the ''Series/{{Sliders}}'' fanbase tend to hold the fanon claim that the Professor Arturo who [[DroppedABridgeOnHim had his brain sucked out, was shot and left to die on an exploding planet]] in "The Exodus, Part 2" was a double of the team's real Arturo, who was left behind by the team (by accident) in "Post Traumatic Slide Syndrome". This is supported by producer Tracy Tormé, who said in interviews afterwards that there was a loose plan to have the "real Arturo" be found when the Slider team return to the planet he was stuck on, but he was [[ExecutiveMeddling shown the door]] before he ever had a chance to put this plan into motion.
* ''Series/{{Smallville}}'':
** There is a reasonably prevalent theory that Lana is also a meteor freak with the ability to make everyone, or alternatively just Clark and other meteor mutants, love her in some form. Lana herself is typically unaware of her power.
** Lex has mutant healing powers. It explains his quick recoveries, the fact that his constant brain injuries haven't killed him yet, and why he's so interested in meteor mutants.
* ''Series/StargateSG1'':
** When Stargate Command started using the gate retrieved from Antarctica, fans noticed that the point-of-origin glyph was still the "sun setting over a pyramid" one from the Giza gate. This is understandable since that symbol is associated with both the show and the SGC in-universe. However we know for a fact that the Antarctic gate had a different point-of-origin symbol (which looked like the sun rising over the curve of a planet). Fanon has it the glyph was vandalized by the Jaffa and Goa'uld that used the gate after the Giza one was buried. Since the pyramid is a symbol of Goa'uld power, this actually makes perfect sense; but why did they leave the glyph on the Dial-Home Device intact?
** A very common fan theory is that the stargates impart knowledge knowledge of any language spoken by anyone who has passed through the gate, to explain why there are so many AliensSpeakingEnglish.
* ''Series/StarskyAndHutch'':
** Starsky's father was a cop named Michael who was murdered by the mob. His mother's name is Rachel. (The episode "The Set-Up" drops some vague hints about Starsky's murdered father, who had some kind of connection to a mobster.)
** Starsky served in UsefulNotes/TheVietnamWar. (The episode "The Plague" mentions that he was in the army, but doesn't give any details.)
** Hutch's father's name was Richard. He was rich but a bad parent, ranging from emotionally distant to outright abusive.
* ''Series/Supergirl2015'':
** Fanworks usually pin the Danvers as being Jewish.
** Due to the prevalence of the FanPreferredCouple Kara/Lena, much of the fandom pins Kara as bisexual. A growing amount of these fans pin her as a soft butch bisexual and Lena as either a femme lesbian or a femme bisexual.
** Some works have her using [[OhMyGods "Oh Rao"]] when surprised. She uses "Great Rao" as a teenager shortly after coming to Earth, but usually uses "Oh my God" as an adult.
** Fanworks usually have Maggie calling Kara "Little Danvers" although Maggie never called her that in the show.
* ''Series/{{Supernatural}}'':
** Fanfic featuring Anna before she became human will almost invariably call her 'Anael', a piece of Fanon Anna's actress herself agreed with. This was indirectly {{Jossed}} with the introduction of a new angel character named Anael in Season 13's "Devil's Bargain".
** It's surprisingly accepted that Dean was either sexually abused (by someone else, [[RonTheDeathEater not John]]) or at least used sex inappropriately when he was younger. Hell, even his [[Creator/JensenAckles actor]] thinks he prostituted himself to pay the bills.
** The brothers have been MistakenForGay on multiple occasions, denied it, and have had numerous heterosexual relationships. Some fans are convinced that they're not only gay, that they're [[NoBisexuals only gay]], and they are interested in each other. This was directly {{jossed}} by canon in a FandomNod, yet it hasn't stopped the shippers. Then again, this is the same fandom that believes the ''actors'' themselves are dating, to the extent of believing that their longtime girlfriends, now wives, are both TheBeard and hired by CW marketing.
** A much more popular theory is that Dean is a closeted bisexual (be certain of hearing about [[StupidSexyFlanders Doctor]] [[GuiltyPleasure Sexy]]). Since Castiel's introduction in Season Four, this is often accompanied by the belief that [[FanPreferredPairing he and Castiel]] are romantically involved. The showrunner (which?) and Creator/JensenAckles have both rejected this interpretation.[[note]]Though at least on the Destiel side, Creator/MishaCollins tends to support the pairing more often than not[[/note]] Writers in Season 10 tried to offer a compromise in the episode "Fan Fiction" (yes, really), welcoming fans to invoke DeathOfTheAuthor and [[FanonDiscontinuity dismiss whatever parts of canon don't work for them]] if they'd prefer to stick to their fanon.
*** A lot of bisexual-Dean fanworks also interpret his father John as a HeteronormativeCrusader to explain why Dean [[HaveIMentionedIAmHeterosexualToday acts so aggressively heterosexual]] with the reasoning that he didn't want to disappoint his father or was afraid of how he'd react if he found out his son wasn't straight. While John [[ParentalAbandonment wasn't exactly an exemplar of parenting]] in canon, there's no real evidence that he was specifically homophobic or anti-LGBT.
** It was also popular to interpret Castiel as asexual based on his abject failure to sleep with the prostitute Dean hired for him in a season 5 episode and his general cluelessness about romance and sex compared to other angels like Gabriel or Balthazar who happily indulged in sex with humans, or gay based on the aforementioned failing-to-sleep-with-a-prostitute scene and his HoYay with Dean. The final season confirmed that he really did have romantic feelings for Dean, but the exact nature of his sexuality beyond "not heterosexual" is still murky especially since he did express romantic/sexual interest in a couple of female characters during seasons 7-9.
** A review for one ''Supernatural'' fanfic said that "Dean wouldn't be able to call Sam 'Samantha' anymore". As a matter of fact, Dean has never used that particular insult outside of fanfics (and not this one, other ones). Apparently this meme got to the point of the reviewer thinking it had happened in the show. While Dean never called Sam that however, Crowley has as one of his endless ways of [[{{Troll}} pulling Sam's pigtails]].
** After [[DarkActionGirl Abaddon]] was introduced and revealed to be a Knight of Hell, fans began speculating that [[TheDreaded Lilith]] and [[TortureTechnician Alastair]] from early seasons had been ones as well: Lilith because her being the first demon turned by Lucifer fit with the description of Knights as the first demons handpicked by Lucifer, and Alastair because both he and Abaddon shared immunity to [[OneHitKill Ruby's Knife]]. This despite Abaddon being a black-eyed demon and Lilith and Alastair being white-eyed demons - eye color generally being a show of where the demons fall on the demon hierarchy (black-eyed demons are usually the weakest and lowest ranking, but Abaddon is a big exception). Although Abaddon was supposed to be the [[LastOfHisKind Last of Her Kind]] of the Knights in the 1950s at the same time Lilith and Alastair were alive, even her turning out to be alive came as a shock to the one who later provided exposition so theoretically they could've also been believed dead. This was mostly due to what little information was known about the Knights at the time and was effectively Jossed for both Lilith and Alastair by the Knights' background being explained in more detail in "First Born" by a more reliable source of information - the demon who really made, and ultimately killed, the Knights.
** Castiel's wings are almost always depicted as black in fanworks which is probably based on him displaying black shadows of them in his introduction scene, even though these were only ''shadows'' and his actual wings (which he doesn't show because his true form would burn humans' eyes out) might be differently-colored.
** Many Dean/Castiel fics portray Castiel as being able to see Dean's soul and falling in love with him specifically because his soul is uncommonly beautiful or pure compared to other humans'. This is in spite of Castiel being quite critical of Dean during the early seasons, even admitting that he thought Dean was just a "broken, bitter shell of a man" while apologizing to him, which is not exactly the kind of behavior you'd expect of an angel supposedly enthralled with his charge's brilliance/purity from the get-go.
** Another popular Dean/Castiel headcanon is that Dean has a part of Castiel's grace inside him as a result of Castiel pulling him out of Hell or healing him so many times over the years. While it is canon that an angel possessing a human leaves traces of their grace inside that human, it's not known if there are other angelic actions that could cause the same effect.
* ''Franchise/SuperSentai'':
** ''Series/SamuraiSentaiShinkenger'':
*** Chiaki went to college after the events of the series. Ryunosuke tells him to study for college entrance exams (and Chiaki complains) but he never expressed a desire to go to college - he considered traveling like Genta.
*** Most fans accept that Kotoha is the youngest of the Shinkengers but there's nothing in canon to state this. She could just be the same age as Chiaki, but he treats her as a little sister figure.
*** Kaoru is somehow related to Shun from ''Series/DenjiSentaiMegaranger''. Both he and Kaoru's father are played by Masaya Matsukaze.
*** Chiaki and Kotoha having twins shows up very often in fanfics pairing the two.
** Some ''Series/GoseiSentaiDairanger'' fans believe Kou and Lin are married by the time of the WhereAreTheyNowEpilogue. This is probably based on Lin having photos of Kou in her house (he does not appear in person) but given the age gap of at least 10 years, and Lin's distaste at Kou hitting on her, it seems unlikely they would have hooked up.
** ''Series/EngineSentaiGoOnger'': Hiroto and Miu are twins. Their ''Franchise/PowerRangers'' counterparts are twins, but while Hiroto is acknowledged to be older than Miu (and looks much older) their ages are not confirmed.
** ''Series/ChoujinSentaiJetman'': Fan opinion differs on whether or not [[spoiler:Gai]] is really dead. [[spoiler: The tie-in manga sequel states he is, but not all fans take it as canon]].
*** [[spoiler: ''Series/KaizokuSentaiGokaiger'' also confirms that Gai is dead. However, due to FanonDiscontinuity the debate continues]].
** Sugishita from ''Series/BakuryuuSentaiAbaranger'' is a wizard, time-traveller, or controls entry to different dimensions. Comes from the Dino Curry House being used as an InnBetweenTheWorlds in the Vs specials, but this appears to have been dropped as of ''Shinkenger vs Go-onger'' with the death of Sugishita's actor.
** ''Series/TokusouSentaiDekaranger'': Umeko is the leader of the Dekarangers. Appears to be more of a RunningGag than anything else. The closest they have to a leader on-screen is Doggie.
** ''Series/TensouSentaiGoseiger'': The Goseigers are ReallySevenHundredYearsOld. WordOfGod gives them ages between 17 (Moune) and 24 (Hyde).
** ''Series/NinjaSentaiKakuranger'': The Kakurangers all have the same family names as their legendary ancestors: Ōhōri Tsuruhime, Sarutobi Sasuke, Kirigakure Saizou and Miyoshi Seikai.
** ''Series/KaizokuSentaiGokaiger'': Marvelous was born and brought up on a pirate ship, or otherwise joined his first pirate crew while still a young child.
*** Luka was engaged to her friend Kain before she joined the Gokaigers. This was never mentioned in his only canon appearance (where he tries to persuade Luka to leave and return to their home planet with him.)
** ''Series/TokumeiSentaiGobusters'': One bit of widely accepted fanon is that Masato Jin is Yoko's father. He is shown to have been a friend of her mother (with the implication of romantic interest) and be very protective towards Yoko, but the show confirms nothing either way.
** There's similar fanon for ''Series/JukenSentaiGekiranger'' of Gou Fukami being the father of Miki's daughter. Miki is often assumed by fans to be a single mother, even though her husband is mentioned and briefly seen in one episode.
*** With [[spoiler:Rio being reincarnated as a young boy]] at the end of the show, it's common fanon that [[spoiler: Mele was also reincarnated and they'll meet again and resume their fated love.]]
** With ''Series/ZyudenSentaiKyoryuger'' leaving Daigo and Amy as the OfficialCouple, some fans have now decided that the two would have a child who marries one of Meeko's children, explaining why Daigo's future great-grandson uses the Tobaspino battery. Along the same lines is the idea that Utchy's and Yayoi's respective children married in the future which is why his descendant Uuppi is [=KyoryuViolet=]. [[spoiler:Of course, in the actual special, it turned out that the batteries the future team members were given were just the only ones Candelira and Luckyuro could find lying around the base, and they were actually destined to use the original team's six batteries. That doesn't totally disprove those theories, but it makes them not quite as necessary.]]
*** Amy and Go-Busters's Yoko becoming college roommates after the events of ''Kyoryuger Vs Go-Busters''.
* In ''Series/Ultraviolet1998'' some fans believe (and the packaging of at least one DVD release outright states) that the central characters' un-named organisation is called the CIB. This is a misinterpretation of dialogue in the first episode, in which their cover story when dealing with the police is that they're members of the Complaints Investigation Bureau, the name at the time of the Metropolitan Police's InternalAffairs squad.
* ''Series/TheVillainsOfValleyView'': Amy being a lesbian is a very popular head canon in the fandom. It helps that Amy doesn't have much in the way of romance with any male characters and that her friendship with Hartley is loaded with LesYay.
* ''Series/{{Victorious}}'':
** In fanfiction, Jade and Beck often reveal their full names are Jadelyn and Beckett. There's been no indication in canon that their names are anything but Jade and Beck.
** Cat is on the autism spectrum and/or has a mental illness. Just what varies, but bipolar disorder is common due to her season 1 personality.
** In canon, Jade loves scissors because her favorite film involves a scissor-wielding killer. Fans, however, think she {{self harm}}s.
** Jade has AbusiveParents.
** Jade, Tori, and/or Cat as bisexual/pansexual is common amongst fans.
** Sikowitz shipping Jade and Tori together is very commonly agreed on in the fandom.
* ''Series/TheWestWing'':
** In fanfics, C.J. calls Josh "mi amore" (a one-off pet name) regularly and very frequently.
** It's basically considered a given that in the future, Sam becomes the President and Josh his Chief of Staff. Writing a story that implies or outright says this didn't happen is tantamount to AU (however, this future is ''strongly'' implied/foreshadowed in canon, so it's not just a fan bandwagon).
** There's a widely accepted explanation for why the presidential election years in TWW are two years offset from when they are in real life (Bartlet was elected in 1998 and re-elected in 2002, as opposed to the real life elections of 2000 and 2004): in the show's universe, when Nixon resigned, instead of Ford succeeding him, there was a special election, the winner served a full four-year term, and things carried on as normal from there. This fits neatly into canon since no nonfictional presidents more recent than Nixon are mentioned on the show.
** A strange mix of fanon and FanonDiscontinuity — in one episode, Leo states that he has only been friends with Jed for eleven years, but has known him for 32. Fans usually ignore this, partly because a [[SeriesContinuityError contradictory statement]] that implied Jed was friends with Leo for 40 years just made more sense to the fandom and is taken as canon instead, partly because the whole "eleven years friendship, 32 years acquaintance" thing was never explained, implied, or mentioned again.
** Fans universally agree that Josh and Donna] marry and have kids. Most also agree that their kids would be named either Noah (for Josh's father), Leo (for Josh's father figure and mentor) or Joanie (for Josh's sister who died in a fire while babysitting Josh). If you take the official twitter accounts as canon they actually do have three children -- Leo, Jacqueline Joan and Noah (though Noah is a girl).
* ''Series/TheXFiles'':
** "Dreamland" dealt with time paradoxes and [[FreakyFridayFlip body-switching]]. Everything gets set back to normal and the whole universe goes back to the way it was before the time rip — but Mulder's apartment is still cleaned up and has a waterbed, and Scully still has a dime and penny that were fused together by the warp in space-time, even though the events that caused both scenarios never happened. It could be explained that they weren't in the path of the snap-back. But how would time snap back for the whole universe then? A fan theory holds that the time loop in "Monday" later in the same season was triggered by the universe repairing itself and trying to get rid of Mulder's waterbed, the last remaining evidence of the paradox. This makes a surprising amount of sense when you watch the episode — the starting point for each loop is the waterbed springing a leak.
** Scully is frequently nicknamed "The Ice Queen" in fanfic, but never on the show.
** Bill Mulder is more often than not portrayed in fanfic as having been an [[AbusiveParents abusive father]], whether it be physically, sexually, or both. While the Mulder family was doubtlessly dysfunctional and Bill's ethics are very questionable, there's no canonical evidence he did anything that heinous to his son.
** Common in the 90's era fanfics was a specific setup for Mulder and Scully's hotel rooms; adjoining rooms, door in the middle connecting them. While this was certainly not the case in canon ("Bad Blood"), fans just used the events of that episode to ''justify'' them going to that setup. Reasons for that setup vary from pragmatism (Hey, if MonsterOfTheWeek shows up, back-up is within range to hear and intervene) to shipping.