From Wiktionary, the free dictionary
From future + fic.
futurefic (plural futurefics)
- (fandom slang) A fanfic set in the future relative to the time in which canonical events are set.
1998 July 23, Eyeglazer [username], “A Glimpse of the Future [futurefic]”, in alt.games.final-fantasy[1] (Usenet):It all inspired me to write this sort of mini futurefic, a look at what might happen when what we once knew is gone.
2001 July 1, Michael Aulfrey, “Argh! Which one to write?”, in alt.tv.x-files.creative[2] (Usenet):A futurefic involving a grown William Mulder looking for his...parents...with John Doggett playing an adoptive "uncle"?
2001 September 10, Lisamichelle, “NEW: Aftermath: EPILOGUE (1/3) NC-17”, in alt.tv.x-files.creative[3] (Usenet):A futurefic following Mulder and Scully over twenty years as they deal with a personal tragedy and the aftermath it leaves.