There is sadly no <10k or <50k words filter on ff.net, and I also couldn't find a c2 for them, nor filter by chapter amount upon completion. What I am looking for is great one-shots like The Birth of Evil and Dumbledore's Monster. Well, any that you think are great. Any fandom
I read a lot of fanfics, but the only one shot that I recently read and still remember is just Blue Fire, Yellow Flames by Luki https://archiveofourown.org/works/17223464 KHR X BnHA My other recommendation is Finding Your Wings by blazonix, One Piece Fandom. it's still unfinished, but part of that story collection in AO3 was something titled silly and strange, I think? It was an AU of Finding Your Wings where the pair was Kuina and Mihawk, and it's already finished. It's fun and 10/10 would read again.