These are all GLs:
https://www.mangago.zone/read-manga/run_away_with_me_girl/
https://www.mangago.zone/read-manga/oniisama_e/
https://www.mangago.zone/read-manga/to_die_in_june_one/ (read the last two chapters here: https://www.mangago.zone/read-manga/to_die_in_june/)
https://www.mangago.zone/read-manga/vampire_chan_junior_chan/
https://www.mangago.zone/read-manga/living_will/
https://www.mangago.zone/read-manga/seasons_in_bloom/
https://www.mangago.zone/read-manga/kago_no_shoujo_wa_koi_wo_suru/
https://www.mangago.zone/read-manga/huijin_huayuan/
https://www.mangago.zone/read-manga/yume_no_hashibashi/
https://www.mangago.zone/read-manga/tower_of_campanella/
https://www.mangago.zone/read-manga/composing_spring_in_this_room_where_cherry_blossoms_bloom/
https://www.mangago.zone/read-manga/kimi_to_tsuzuru_utakata/
https://www.mangago.zone/read-manga/kimi_ga_shinu_made_koi_wo_shitai/
https://www.mangago.zone/read-manga/a_monster_wants_to_eat_me/
https://www.mangago.zone/read-manga/haru_and_midori/
https://www.mangago.zone/read-manga/ohana_holoholo/
https://www.mangago.zone/read-manga/throw_away_the_suit_together/
https://www.mangago.zone/read-manga/getting_to_know_grace/
https://www.mangago.zone/read-manga/i_love_amy/
https://www.mangago.zone/read-manga/the_sound_of_a_butterfly/
https://www.mangago.zone/read-manga/sayonara_rose_garden/
https://www.mangago.zone/read-manga/kono_koi_wa_hoshi_ni_wa_negawanai/
https://www.mangago.zone/read-manga/the_wind_spell/
https://www.mangago.zone/read-manga/dark_mermaid/
https://www.mangago.zone/read-manga/artificial_temperature_36_7_c/
https://www.mangago.zone/read-manga/have_a_great_trip_after_the_credits_roll/
https://www.mangago.zone/read-manga/this_love_that_won_t_reach/ (age gap, MC is in love with her sister-in-law;rushed and ambiguous ending)
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_story_of_a_person_who_grew_a_flower/ (short story; age gap, teacher-student relationship;hanahaki disease)
https://www.mangago.zone/read-manga/final_film/ (short story)
https://www.mangago.zone/read-manga/shiroi_heya_no_futari/ (one-shot)
https://www.mangago.zone/read-manga/141108/ (one-shot)
https://www.mangago.zone/read-manga/aliens/ (one-shot)
https://www.mangago.zone/read-manga/the_story_of_the_princess_and_the_little_mermaid/ (one-shot)
https://www.mangago.zone/read-manga/escape_into_oblivion/
https://www.mangago.zone/read-manga/swallow_gawee/
https://www.mangago.zone/read-manga/yoake_no_uta/
https://www.mangago.zone/read-manga/10_years_where_i_loved_you_the_most/
https://www.mangago.zone/read-manga/zankoku_na_kami_ga_shihai_suru/
https://www.mangago.zone/read-manga/stigma_marloong/
https://www.mangago.zone/read-manga/death_delayed_for_a_short_time_because_of_the_will/
Can you guys recommend sad/tragedy BL/GL plsss!?!