I've seen this before :/ But thank you though!
try pupa
Is light horror but seriously http://www.mangago.zone/read-manga/oh_lord_jesus/ good
http://www.mangago.zone/read-manga/battle_royale/ is the best of the best!
or
http://www.mangago.zone/read-manga/imawa_no_kuni_no_alice// This manga was soooo good, it play so much with your mind!
oh ok np ^^ sorry I don't know much horror but looks like there are some good ones here (●'◡'●)ﾉ
I don't want cliches, trapped on an island (forced to kill each other kinda thing), or a zombie apocalypse etc.
I've read all of Junji Ito's stories, Starving Anonymous, A Trail of Blood, Jinmen... I can't name anything else off the top of my head.
Maybe something like Starving Anonymous can work. Thank you in advance!