Sometimes writers, artists, and other people involved in a work take to their series so much that they make their own Fan Works. These are non-canon or at most semi-canon, though fans tend to take them more seriously than fan works created by ordinary fans. The quality of the fan works varies, but many are rather in-character or on-model thanks to the person's experience with the series.
There are various mangakas that started in hentai before making SFW mainstream works, but some of them continue making hentai fanworks (some of them Spin-Off of their own series) under different pen names and doujinshi circles. Some examples are Hiromitsu Takeda, Kouta Hirano and Masamune Shirow.
The inversion of Official Fan-Submitted Content, which is when fans make contributions to a specific work.
Can run into What Do You Mean, It's Not for Kids?, if the source work is kid-friendly but the fan work is not, only to fool more easily because the creator works on the source officially. Compare to Running the Asylum, Word of Dante, Word of Saint Paul, and Bleached Underpants. Can often be found on a Line to God. Contrast with Fanwork Ban, which is when creators disapprove of fan-works, Promoted Fanboy, for when someone who previously made fan-works is allowed to officially contribute to the work they're making fan works of (said fan may still make fan works of said work after that), and Ascended Fanon, for when fan works and ideas are canonized.
- Vic Mignogna, Edward's English voice, is a huge fan of Fullmetal Alchemist, especially the 2003 anime. He has created the Filk Song "Nothing I Won't Give" and has even created a Fan Film called Fullmetal Fantasy about the series (which he's not legally allowed to distribute online).
- Jun Sasaki, one of the creators of Panty & Stocking with Garterbelt, had the story left incomplete because the series was cancelled after season 1 and he departed from Studio Gainax to Studio Trigger, where he created Space Patrol Luluco. After that, he created a dōjinshi called Juice, a crossover between Panty & Stocking and Luluco where both series are part of a Shared Universe and he gave an end to the sudden Gainax Ending at the end of P&S's season 1 mixed with the ending of Luluco's (where Brief collected all Panty's pieces and assembled her again but with something wrong, and Nova reappears with Identity Amnesia). If this is canon or not is debatable, but it's valid for the fans at least.
- Dragon Ball has its fair share of animators, artists, and writers over the series' run that have produced fan works as a result of its cultural impact. Some were brought into the franchise because of their fan resume:
- fenyo_n is a Japanese promotional character artist for modern-era Dragon Ball products, such as Dragon Ball Z Dokkan Battle and Dragon Ball Heroes. On their social media accounts note , they produce What If? illustrations and comics based on moments in the series or their recent commissioned work.
- Masaki Sato, a famous Dragon Ball animator notable for animating the original and iconic Super Saiyan Goku transformation, has done plenty of illustrations on the series since his departure during the Z-era on his Twitter. Som Ever wanted to see Slam Dunk's Hanamichi Sakuragi note teaming up with Vegetto?
- Yuya Takahashi, a fan favorite freelance animator of the modern era of Dragon Ball, also does some pieces based on episodes he's animated, a few pieces for Dragon Ball Super: Broly, and even some character design studies.
- Toyotarō was once a fan manga artist before officially writing and illustrating the Dragon Ball Super manga. He hasn't lost this knack for imagining What If? scenarios, so he makes a separate series called "Toyotaro Drew It!", where he draws some side or obscure characters and muses some non-canonical details about them.
- Dragon Garrow Lee, another fan mangaka who was officially brought into Dragon Ball to pen Dragon Ball: That Time I Got Reincarnated as Yamcha!, draws a considerable amount of fan pieces regarding his favorite character, Yamcha, along with other franchises on his Twitter.
- Kaishaku created two Destiny of the Shrine Maiden hentai doujin, with one being a crossover with Magical Meow Meow Taruto.
- While working on the Warrior Cats Tigerstar and Sasha manga, illustrator Don Hudson posted a couple sketches he did for fun: a Halloween one of what appears to be the villain Tigerstar as a cat-headed man, and one layout where the final panel was replaced with Sasha walking to Mordor.
- There was a fan-created Neon Genesis Evangelion video mockup of sequel or AU that got the voice acting of a couple of the original English dub voice actors, including Tiffany Grant.
- One of the main writers on Sonic the Comic, Nigel Kitching, has collaborated with the people behind the Fan Sequel Sonic the Comic Online! a few times. His final STC comic is a Distant Finale set at minimum ten years after anything either in Sonic the Comic or Sonic the Comic Online. The comic, amongst other things, made Amy and Tekno being together all-but Ascended Fanon.
- Artist Stjepan Sejic does art for Marvel Comics and DC Comics as well as his own projects. On Twitter, his fan art of Lara Croft meeting Wonder Woman is a hit.
- Dan DeCarlo created the signature Archie Comics art-style but he also drew fanart of the characters. Quite a sum of it was NSFW art about Betty and Veronica.
- Mauricio Herrera, one of the creators of Diablo made a career of his own after he left the comic book as a freelance artist as El-Grimlock, where he also created Fan Arts of different characters; some of them included illustrations of his previous works on Diablo and Mitos y Leyendas, and with the former he even made a crossover between Batman and Diablo.
- The Filth has an in-universe example, where Secret Original mentions that Moog Mercury, one of the writers for Status Quorum, has been creating pornographic AU stories featuring the characters. This greatly disturbs Secret Original, as he used to be one of those characters before he ended up in three-dimensional space.
- Before working as an artist and then a writer in Sonic the Hedgehog (Archie Comics) and Sonic the Hedgehog (IDW), Evan Stanley worked in her own fancomic, Ghosts of the Future, which she still works on.
- One of the Warrior Cats authors wrote a short story called "The Longest Night" featuring the cats' You Mean "Xmas" equivalent, and ended up getting into trouble with the editors for it.
- S. E. Hinton, writer of The Outsiders, published multiple anonymous fanfictions based on her own novel.
- Lisa Williams, author of Family Bites, wrote two filks and some "Very Secret Diaries"-style fanfic. One filk was posted on alt.fan.pratchett, the rest appears to have been lost with the Family Bites website.
- Courtney Milan wrote a short non-canon time-travel/alternate-dimension crossover between her Brothers Sinister series (Victorian historical romance with a dash of Alternate History) and her Cyclone series (contemporary romance set among Silicon Valley tech types). She posted it on her website with a note specifically mentioning that she has no intention of introducing time travel and its attendant can of worms to either 'verse.
- Rose Lerner, another romance novelist friendly with Milan, has posted side stories about her own work that incorporate fanfic tropes. Canon is pure historical romance set in early 19th-century Britain or late 18th-century America, but the side fics include a modern AU pairing the heroine of one book with the heroine of another, a modern AU where two side characters go to IKEA, yet another modern AU where two of the characters go on a reality TV baking show, an AU where the hero is a vampire and the heroine is a dragon, and a Five Things story.
- Matt Smith supposedly wrote Fan Fiction privately to get into character as the Doctor in Doctor Who, although none of it was ever made public.
- After Andromeda finished its run, the original head writer put out Coda where Trance explains an alternate history which is what he would have done with the series if he hadn't been fired during the second season.
- Soraya Saga, one of the scenario writers in Final Fantasy VI, created a doujinshi that elaborated further on the past lives of Edgar and Sabin, two characters she's credited for.
- David Gaider:
- After leaving BioWare, David Gaider published a short story about Dorian Pavus from Dragon Age: Inquisition. Since he no longer works for the developer, it's technically fanfic, but most fans regard it as canon since Gaider was Dorian's writer.
- David Gaider also created "Ascension", one of the better-known mods for Baldur's Gate II: Throne of Bhaal. It wasn't an official BioWare release, but adds or restores content that Gaider, as one of the game's writers, personally wished had made it into the official product.
- Gaider pulled a hat trick with this in Knights of the Old Republic by submitting a story called "Denouement" to kotorfanmedia.net, saying it was his headcanon as to what happened after the game. It ended up adding to a fandom controversy later, as Lucasarts canonized the opposite gender.
- Several of the mappers for Unreal Tournament which worked in the game released several maps as Downloadable Content, without the Epic Games or Digital Extremes names attached to them. Some of these maps are Inoxx's DM-Gen][ (the Skaarj Mothership level from Unreal as a Deathmatch map) and Myscha's CTF-Command][ (a symmetrical version of CTF-Command made for clan games).
- C0DA is an unofficial graphic novel script for The Elder Scrolls by former series developer Michael Kirkbride meant to encourage the idea of The Elder Scrolls lore as a living open-source world.
- Touhou Project:
- Makoto Hirasaka had done some Touhou doujinshi before becoming the main artist on Touhou Sangetsusei, and has continued with them afterwards, most notably Three Fairies, explaining how the main characters of Sangetsusei, the Three Fairies of Light, first met, and Three Fairies ~Little Stone Heart~, in which the Three Fairies meet Kokoro and Koishi.
- Similiarly, Aya Azuma, the artist on Touhou Ibarakasen ~ Wild and Horned Hermit, has done several doujinshi both during and after working on it, most notably The Shinigami's Rowing Her Boat As Usual, a series following Komachi's life, released as a free web manga on the Strange Creators of Outer World website.
- The Doom mod Sigil was created by John Romero, a former designer for the series.
- Claire Hummel, one of the character artists for BioShock Infinite, upon seeing porn of the Lutece twins, remarked that she was upset that people were drawing them in period-inaccurate underwear.note The artist then provided a visual guide on what sorts of undergarments Rosalind Lutece would actually wear.
- Suriko, one of the main writers for Katawa Shoujo, wrote "Summer's Clover" as a fake route for Miki, one of the game's Ensemble Dark Horses. A group of fans later took this a step further by turning "Summer's Clover" into a full-blown VN of its own. Another developer, Aura, wrote a shorter fanfic called "Pedagogy".
- Rooster Teeth's Death Battle features characters from RWBY, including the titular Team RWBY, in battles to the death with Mitsuru, Mikasa, Inuyasha, Tifa, Bakugo, Ragna, and Chun-Li. However, there isn't bias towards RWBY, as Weiss loses to Mitsuru, Blake loses to Inuyasha, and Yang loses to Bakugo.
- Illustrator and toy designer Amy Mebberson has drawn for several Disney Comic Books and worked as an inbetweener for several Disneytoon Studios films before gaining notoriety for her Fan Webcomic Pocket Princesses. Her case would later overlap with Promoted Fangirl when she got to work on the official Disney Princess comic books.
- Avatar: The Last Airbender storyboarder Johane Matte has created two webcomics based on the series: Alternate History takes place in an Alternate Universe where Aang escapes the iceberg twenty years later than in canon. Water Tribe is a Zhao-themed comic.
- Layout artist and character designer Antonia De Pieri also produces fan-art for various fandoms, including those she works on like Carmen Sandiego.
Antonia: This morning I got the okay from the higher ups to post fan art so y'all are in for a Ride.
- The storyboarders for episodes of Steven Universe would usually draw art to promote the episodes they boarded, in addition to random doodles and sketches. In particular, former storyboard artist Hilary Florido drew art of the characters in a High School A.U. whenever one of her episodes aired.
- Raven Molisee, a storyboard artist for Ed, Edd n Eddy, Steven Universe, and My Little Pony: Friendship Is Magic has her own DeviantArt account where she posts her Fan Art for various cartoons.
- Thomas Perkins, a prolific character designer on many 2000s and 2010s shows, did some What If? pieces for The Avengers: Earth's Mightiest Heroes!. Some of them might as have been episodes in themselves, like the X-Men teaming up with the Avengers, the next generation of Avengers, a copyright breaking appearance of ROM: Space Knight, and more fantastical tales.
- In a charity livestream, Noelle Stevenson, the creator of She-Ra and the Princesses of Power, revealed they wrote a Catradora fanfiction and posted it to Archive of Our Own, but declined to reveal its title or their username, though they did provide a couple tantalizing hints for the fanbase, who naturally went wild trying to find it. Most agree it's probably the fic Don't Go, but Noelle hasn't confirmed or denied this. The fic is now commonly accepted as canon by the fanbase, since it doesn't contradict anything we see onscreen and in fact fills in a couple gaps. (Many have also noted that this leads to the amusing mental image of some random, unknown fic authors waking up one morning to their stories having suddenly gained tons of hits overnight, alongside some comments accusing them of being Noelle, and probably being very confused as a result.)
- Noelle was also known for drawing Adora with scars in the shape of scratches, leading to popular speculation that the scars were from Catra, and nearing the final season, later speculated to be from Horde Prime), though the scars ended up never happening in the show. It's been presumed by fans that this is along with her mystery fanfic provide evidence that Noelle has personal AUs.
- Tangled: The Series has Kait Ritter and Anna Lencioni's Varian and the Seven Kingdoms AU (Ritter's Tumblr), a sequel to the show focusing on the adventures of Varian and his companions — his apprentice Yong, his rival Hugo (a character transplanted from Ritter and Lencioni's D&D campaign), and a princess named Nuru — as they journey across the Seven Kingdoms to discover what happened to Varian's long-lost mother.
- Miraculous Ladybug:
- The show's creator Thomas Astruc has created historical Ladybugs and Cat Noirs and posts about them on his social media, though has no solid plans for bringing them into the show. Though there was a comic series announced to focus on this, it has since been stuck in Development Hell.
- Ferisae, who handles PR and owns the official Mexican Twitter for the show (Miraculous Mexican), has made OCs expanding on Astruc's historical Ladybugs and Cat Noirs.
- Astruc has gone on record saying that some things are created by Jeremy Zag and that there's not much he can do about it. The Miraculous World specials for Rio, Japan, and Africa, Lady Butterfly being transplanted from Pixiegirl to be the Brazilian Miraculous user in the Rio special, the Ladybug and Cat Noir retelling films, any possible crossovers with Ghost Force, and so on, were made by Zag and not under Astruc's vision.