I think pumpkin night fits that idea.
https://www.mangago.me/read-manga/pumpkin_night/
Girl is horribly bullied and goes on a revenge killing spree. I can't remember if she's the Mc or if the Mc is one of the bullies.
Manga (about revenge)
https://www.mangago.me/read-manga/ijimeru_aitsu_ga_waruinoka_ijimerareta_boku_ga_waruinoka/
https://www.mangago.me/read-manga/brutal_satsujin_kansatsukan_no_kokuhaku/
https://www.mangago.me/read-manga/maria_no_danzai/
Bl w revenge plot (contains rape)
https://www.mangago.me/read-manga/hardcore_bl_anthology_the_tosa_s_master/
https://www.mangago.me/read-manga/hit_me/
https://www.mangago.me/read-manga/sheep_s_mask/
recommend some horror stories? Either supernatural or gore but like if It's gore maybe something with revenge? Like someone going ham with their revenge and just fucking everyone up