Keep Circulating the Tapes/Fan Works

• The Star Trek fanfic "A Fragment out of Time" by Diane Marchant — the first Kirk/Spock fic ever written, and the story that spawned Slash Fic as a genre — exists today only in its original zine, Grup 3, which is extremely rare. The story was never posted online. The only way to read it is to hunt down the zine in used bins at conventions. The University of Iowa Library, however, hosts a special collection of early fanzines, including Grup 3 and the zine that contained Marchant's defense of K/S — Grup 4.
  • This is actually true of many of the early fic written in zines, as many authors never made the switch to the Internet.
• Any fanwork in a fandom under a Fanwork Ban usually becomes this. As most sites are pulled for fear of invoking legal wrath, some fanworks are made available through shady underground communities.
• Computer Boy, an Australian parody of The Matrix. No DVD release and only available as a low-resolution Quicktime download, due to (apparent) legal issues with a scene filmed inside a McDonald's store.
• It has been known for fanfic authors who turn pro to pull their fanfic from the internet, either because they consider it Old Shame, because their publishers don't approve, or because they're strip-mining their fic for ideas for original works and don't want people to make comparisons. The most emblematic cases are Cassandra Clare and her Draco Trilogy, and E. L. James with "Masters of the Universe", the Twilight fanfic that eventually became Fifty Shades of Grey.
  • It's not just ones from authors that turn pro. Any fanfic can just disappear from the internet due to some reason from the fanfic author. Deleting all their content after Rage Quitting a fandom isn't an unusual occurrence. Sure, most of those fics aren't worth reading, but there are some good ones that disappear too.
  • Sometimes, authors tired of their fics being plagiarized or reuploaded without permission pull them from theirs accounts, paradoxically making their plagiarists and reuploaders the only way to read said fics again. One such particular case was Overgrowth a very popular Undertale fanfic that codified the "Flowerfell" AU, that was retired from the author's AO3 account due to being extensively plagiarized (an author-approved podcast reading of the fic still survives in the site, through).
• When an Internet domain goes under, works by inattentive authors using that domain will disappear. The end of Geocities killed quite a few fanfics on unmaintained sites which had been popular enough to stay up by reader visits alone. Ones on Tripod and FortuneCity have also disappeared. While the Geocities ones could theoretically be rescued if they managed to get into the many surviving dump mirrors for the site, the ones on Tripod and FortuneCity, due to being in less "emblematic" web hosts, had not the same fortune.
• Anything that was on Soupfiction and is not in the Wayback Machine.
• Fanfiction.net had Real Person Fic until about 2001, and then removed it all. Some of it is still missing.
  • Most of the R-and-up rated fics that existed in the site before the 2003 purges of mature content are still missing too.
• Any of Racewing's fanfics appear almost completely lost. And that's terrible.
  • Some of them and others on racewing's site can be found here
• The Ranma ½/Sailor Moon Crossover fic Relatively Absent, by Mark "Togashi Gaijin" Shurtleff: an inventive and very well-written example and subversion of the classic Fuku Fic concept. Unfortunately, Shurtleff left the fanfiction scene in 2009 and succeeded in very thoroughly purging this and his other fics from the Net (even from the Wayback Machine). A decade later he still monitors the web for reappearances of his work and sends politely-worded requests to take it down whenever he finds it. However, while no websites host his stories any more, there are still archives being traded from fan to fan; if you can find someone who has them, you can still read his sadly incomplete works.
• Despite her thorough scrubbing of her former websites, many of the Pokémon fics by Cori Falls survive intact if you know where to ask, to the delight of sporkers and fandom historians. Unfortunately, the same cannot be said of her Yu-Gi-Oh fics, who apparently are Lost Forever.