Punk love triangle! Not necessarily goth but close enough
Vampire GLs:
https://www.mangago.zone/read-manga/shoujo_tachi_no_kizuato_ni_kuchizuke_wo/
https://www.mangago.zone/read-manga/seifuku_no_vampiress_lord/
https://www.mangago.zone/read-manga/i_won_t_let_mistress_suck_my_blood/
https://www.mangago.zone/read-manga/my_food_seems_to_be_very_cute/
https://www.mangago.zone/read-manga/killing_me_akiyama/
https://www.mangago.zone/read-manga/koroshi_korosare_sankaku_kankei_ni_watashi_ga_ima_kara_hairun_desu_ka/
https://www.mangago.zone/read-manga/liberta/
https://www.mangago.zone/read-manga/vampire_chan_junior_chan/
https://www.mangago.zone/read-manga/kamitsuki_gakuen/
https://www.mangago.zone/read-manga/scarlet_yuino_chiri/
https://www.mangago.zone/read-manga/gunbured_x_sisters/
https://www.mangago.zone/read-manga/black_backed_albatross/
https://www.mangago.zone/read-manga/kiss_me_in_the_dark_of_night/
https://www.mangago.zone/read-manga/vampires_higashiyama_shou/
https://www.mangago.zone/read-manga/kyuuketsuki_to_yobaretai/
https://www.mangago.zone/recommend-manga/girls_vampire/
https://www.mangago.zone/read-manga/blood_time/
https://www.mangago.zone/read-manga/a_girl_who_longed_to_be_a_hero_aims_to_be_a_hero_even_if_she_falls_into_a_vampire/
https://www.mangago.zone/read-manga/savior/ (toxic relationship, depictions of kidnapping, violence, love triangle - girl A loves girl B, girl B loves girl C, girl C loves girl A)
https://www.mangago.zone/read-manga/the_most_perfect_meal/ (short story)
Mermaid/siren GLs:
https://www.mangago.zone/read-manga/a_monster_wants_to_eat_me/
https://www.mangago.zone/read-manga/seeking_a_beauty_in_the_east_sea/
https://www.mangago.zone/read-manga/the_wind_spell/
https://www.mangago.zone/read-manga/the_siren_s_light/
https://www.mangago.zone/read-manga/the_sea_painted_by_the_moonlight/
https://www.mangago.zone/read-manga/mina_soko_nite/
https://www.mangago.zone/read-manga/dark_mermaid/ (bullying, harassment, child neglect, sexual harassment, sexual assault, blackmail, child abuse, attempted sexual assault on a child - none of these are done by either MC or FL)
Dark GLs:
https://www.mangago.zone/read-manga/isekai_picnic/
https://www.mangago.zone/read-manga/strange_tales_of_kisaragi/
https://www.mangago.zone/read-manga/mietemasu_yo_aizawa_san/
https://www.mangago.zone/read-manga/the_wolf_in_love_and_mille_feuille/
https://www.mangago.zone/read-manga/do_you_think_someone_like_you_could_defeat_the_demon_lord/
https://www.mangago.zone/read-manga/scarlet_yuino_chiri/
https://www.mangago.zone/read-manga/okiku_san_wa_ichatsukitai/
https://www.mangago.zone/read-manga/qualia_the_purple/
https://www.mangago.zone/read-manga/saeism/
https://www.mangago.zone/read-manga/zenbu_kowashite_jigoku_de_aishite/
https://www.mangago.zone/read-manga/i_love_amy/
https://www.mangago.zone/read-manga/the_brave_do_not_fear_yusha_ha_osorezu/
https://www.mangago.zone/read-manga/and_kaede_blooms_gorgeously/
https://www.mangago.zone/read-manga/kago_no_shoujo_wa_koi_wo_suru/
https://www.mangago.zone/read-manga/i_m_more_dangerous_than_you/
https://www.mangago.zone/read-manga/manipulate_my_heart/
https://www.mangago.zone/read-manga/ghosts_of_greywoods/
https://www.mangago.zone/read-manga/liar_satsuki_can_see_death/ (GL subtext only)
https://www.mangago.zone/read-manga/suicide_girl/ (GL subtext only)
https://www.mangago.zone/read-manga/kitanai_kimi_ga_ichiban_kawaii/ (toxic relationship, features some extreme fetishes such as age regression/babyplay, vomit kink, period blood kink, etc.)
https://www.mangago.zone/read-manga/the_onee_sama_and_the_giant/ (violence, gore, sexual harassment, attempted sexual assault)
https://www.mangago.zone/read-manga/naraku_no_hanazono/ (child neglect, incest - not between MC and FL, child sexual assault, child abuse)
Hello! I want goth or anything dark GL & BL please help me.（/TДT)/