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.
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 or 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 Kannazuki no Miko hentai doujin, with one being a crossover with Magical Nyan Nyan 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.
- 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 Archie Comics' Sonic the Hedgehog 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.
- 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.
- 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.
- 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".
- 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 Deviant Art 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.