by fangames I mean games that use characters or locations that already exist in other games/movies/books but you don't own them

Hey there, thanks for asking and it's probably something I should add to the rules section. No, I'd prefer it if only original content was submitted. Fan games are a bit of a gray area, so it's better to just keep them away.
Besides, jams are about showing us YOUR creations, not someone else's.