There are quite a few fan fiction sites out there — the supply is so great (not saying all of it is good - it isn’t)
but it’s amazing that anyone can get paid for fiction writing these days.
I enjoy fan fiction in some cases. I have a few fan fiction novels downloaded that were for the game Thief (PC game from 98,99, “Thief: the Dark Project” and “Thief: The Metal Age”) that were very good.