@0CHAVITY Hi! I'd be glad to give you some recs of fanfics I like on this site, so here are some gems that I've found!
The first is "For We Are One (Various!BNHA x Reader)" by Mariex0x0x. It's an isekai with the reader being transported into the world of MHA, and it's already half-way into season four. It's a story that I had binge-read the first time I found it, so I would think that it's pretty good for having kept my attention for so long. The author is on a break at the moment, but she should be back sooner or later.
The second is "Demoralize (Inverted!BNHA x Reader)" by Isekai_Reader. It's another isekai with the reader being transported into the world of MHA, but, this time, it's into the Inverted!AU, which basically means everything's inverted (heroes are villains, villains are heroes, etc.). Due to the nature of the AU, the story has depictions of violence and abuse, as well as other dark subjects, so I would choose to read it at your own discretion. My favorite part about it would be the reader's personality since, in the authors' words, she has "a suckish way of dealing with conflict". The story is on a hiatus right now, but they should be back sooner or later.
The third, and final, is "Into the World of BNHA (Yandere!BNHA x Reader)" by LadyMinion535. It's, once again, an isekai with the reader being transported to the world of MHA, and, despite being a yandere story, I find it to be quite funny, having references to internet humor and general funny moments with the reader being one setting them up. It takes some time for the yandere feelings to slide in, so it has good pacing, though the writing is informal, fitting with its humor. The story updates infrequently, so it might be quite some time to wait for the next chapter.
So, there you have it, some fanfic recs I can give you. I guess you can assume what my tastes are from all of them being isekai, but, what I can say? I love a good "reader from our world ends up in theirs" story!
Happy reading! :)