Hey, i found sites with many fanfiction with less isekai character. Fanfiction.net
You just need to find a genre and/or character that suits your taste.
I think i remember reding it in different sites, naruto fanfic
- fmc twin sister of sakura that useful
- Naruto that smart and have dark personality
- fmc with Nara blood and uchiha eyes
I forgot the sites.
