"Heartless" (not really horror) (=・ω・=)
https://www.mangago.me/read-manga/dreadful_night/
https://www.mangago.me/read-manga/blood_sacrifice/
https://www.mangago.me/read-manga/radio_storm/
https://www.mangago.me/read-manga/sankaku_mado_no_sotogawa_wa_yoru/
https://www.mangago.me/read-manga/hikaru_ga_shinda_natsu/
https://www.mangago.me/read-manga/madk/
https://www.mangago.me/read-manga/sleeping_dead/
https://www.mangago.me/read-manga/kansai_jin_to_hukuman_satsujinki/
The Night Beyond the Tricornered Window mentioned!!
horror yaoi???