Horror or thriller anything is fine

Might not be quite that level but Starving Anonymous is one of the only manga to ever properly scare and disturb me

Some of these are not that scary but they have really intriguing storylines
https://www.mangago.me/read-manga/chasing_tails/
https://www.mangago.me/read-manga/an_uncomfortable_truth/
https://www.mangago.me/read-manga/ghost_teller/
https://www.mangago.me/read-manga/one_day_suddenly_seoul_is/
https://www.mangago.me/read-manga/pigpen/
https://www.mangago.me/read-manga/monster_child/
https://www.mangago.me/read-manga/distant_sky/
https://www.mangago.me/read-manga/suicide_notes_laid_on_the_table/
https://www.mangago.me/read-manga/the_crow/
https://www.mangago.me/read-manga/ghost_story_club_remake/
https://www.mangago.me/read-manga/dam_of_the_forest/
https://www.mangago.me/read-manga/god_s_id_card/
https://www.mangago.me/read-manga/the_planet_walks_alone/
https://www.mangago.me/read-manga/american_ghost_jack/
https://www.mangago.me/read-manga/sangyang_the_wanderer/
https://www.mangago.me/read-manga/welcome_to_the_rose_manor/
https://www.mangago.me/read-manga/a_ghostly_song/
https://www.mangago.me/read-manga/for_your_murder/
https://www.mangago.me/read-manga/book_of_the_dead/
https://www.mangago.me/read-manga/the_black_june/
https://www.mangago.me/read-manga/detective_xeno_and_the_seven_locked_murder_rooms/
https://www.mangago.me/read-manga/kings_viking/
https://www.mangago.me/read-manga/tomodachi_game/
https://www.mangago.me/read-manga/imawa_no_kuni_no_alice/
https://www.mangago.me/read-manga/lovesickness_junji_ito_story_collection/
https://www.mangago.me/read-manga/venus_in_the_blind_spot/
https://www.mangago.me/read-manga/drcl_midnight_children/
https://www.mangago.me/read-manga/apocalypse_no_toride/
https://www.mangago.me/read-manga/shokuryou_jinrui/
https://www.mangago.me/read-manga/dai_dark/
https://www.mangago.me/read-manga/parasyte_reversi/
https://www.mangago.me/read-manga/hundred_ghost_stories_of_my_own_death/
https://www.mangago.me/read-manga/ajin/
https://www.mangago.me/read-manga/shin_ai_naru_boku_e_satsui_wo_komete/
https://www.mangago.me/read-manga/mononogatari/
https://www.mangago.me/read-manga/aisha/
https://www.mangago.me/read-manga/kamonohashi_ron_no_kindan_suiri/
https://www.mangago.me/read-manga/saiyaku_wa_boku_o_suki_sugiru/
https://www.mangago.me/read-manga/shinrei_tantei_yakumo/
https://www.mangago.me/read-manga/sennen_meikyuu_no_nana_ouji/
https://www.mangago.me/read-manga/ayeshah_s_secret/
https://www.mangago.me/read-manga/silver_diamond/
https://www.mangago.me/read-manga/mystery_to_iunakare/
https://www.mangago.me/read-manga/sankaku_mado_no_sotogawa_wa_yoru/
https://www.mangago.me/read-manga/liar_satsuki_can_see_death/
https://www.mangago.me/read-manga/shadow_house/
https://www.mangago.me/read-manga/boku_dake_ga_inai_machi/
https://www.mangago.me/read-manga/madame_petit/
https://www.mangago.me/read-manga/tengoku_daimaky/
https://www.mangago.me/read-manga/xxxholic/
https://www.mangago.me/read-manga/housekishou_richard_shi_no_nazo_kantei/
https://www.mangago.me/read-manga/akumu_no_sumu_ie_ghost_hunt/
https://www.mangago.me/read-manga/pet_shop_of_horrors/
https://www.mangago.me/read-manga/mayonaka_no_occult_koumuin/
https://www.mangago.me/read-manga/hen_na_ie/

Thanks a lot kind people

https://www.mangago.me/read-manga/fuan_no_tane_plus/
https://www.mangago.me/read-manga/kouishou_radio/
https://www.mangago.me/read-manga/ibitsu/
https://www.mangago.me/read-manga/panorama_of_hell/
https://www.mangago.me/read-manga/hideout/