Threesome:
http://www.mangago.zone/read-
manga/choco_strawberry_vanilla/
http://www.mangago.zone/read-manga/ikenai_otoko/
http://www.mangago.zone/read-manga/mukizu_ja_irarenee/
http://www.mangago.zone/read-manga/love_me_hard/
http://www.mangago.zone/read-manga/hard_core_heart/
http://www.mangago.zone/read-manga/kaikan_fortune/
http://www.mangago.zone/read-manga/glow_vampire/
http://www.mangago.zone/read-manga/koisuru_omocha/
http://www.mangago.zone/read-manga/tsumibito_no_kiss/
http://www.mangago.zone/read-manga/nureru_karada_yamakami_riyu/
http://www.mangago.zone/read-manga/sex_therapist/
http://www.mangago.zone/read-manga/sadistic_boy/
http://www.mangago.zone/read-manga/yoiko_no_sumu_machi/
http://www.mangago.zone/read-manga/rumble_rush/ ch1
http://www.mangago.zone/read-manga/himitsu_no_kuchizuke/
http://www.mangago.zone/read-manga/kunshu_no_ai_wa_yoru_ni_hana_saku/
http://www.mangago.zone/read-manga/kouya_no_seifukuou/
http://www.mangago.zone/read-manga/3_pieces/
http://www.mangago.zone/read-manga/leave_me_alone_with_first_love/
http://www.mangago.zone/read-manga/baby_bitch/
http://www.mangago.zone/read-manga/gorgeous_heart/
http://www.mangago.zone/read-manga/thirsty_for_love/
http://www.mangago.zone/read-manga/pathos/
Love Triangle:
http://www.mangago.zone/read-manga/kasa_no_shita_futari/
http://www.mangago.zone/read-manga/doukyonin_no_binandomo/
http://www.mangago.zone/read-manga/110_ban_wa_uketsukemasen/
http://www.mangago.zone/read-manga/tsumasaki_ni_kiss/
http://www.mangago.zone/read-manga/ao_haru_ride/ (shoujo)
http://www.mangago.zone/read-manga/totally_captivated/
http://www.mangago.zone/read-manga/vampire_knight/ (shoujo)
http://www.mangago.zone/read-manga/ai_o_kou_kemono/
http://www.mangago.zone/read-manga/koi_no_tsumeato/
http://www.mangago.zone/read-manga/unbalance_na_netsu/
http://www.mangago.zone/read-manga/itazura_neko_ni_goyoujin/
http://www.mangago.zone/read-manga/love_in_the_mask/ (shoujo)
http://www.mangago.zone/read-manga/doubt_nishimura_shuuko/
http://www.mangago.zone/read-manga/strobe_edge/ (shoujo)
http://www.mangago.zone/read-manga/sigh_s_kiss/
http://www.mangago.zone/read-manga/can_t_lose_you/ (shoujo)
http://www.mangago.zone/read-manga/kuchibiru_no_yukue/
http://www.mangago.zone/read-manga/desire_sensibility/
http://www.mangago.zone/read-manga/katsubou_no_manazashi/
http://www.mangago.zone/read-manga/obaka_chan_koigatariki/ (shoujo)
http://www.mangago.zone/read-manga/aijin_wa_korosareru/
http://www.mangago.zone/read-manga/cheonsaeng_yeonbun/ (shoujo)
http://www.mangago.zone/read-manga/kimi_no_kao_ni_sasu_kage/
http://www.mangago.zone/read-manga/rin/
http://www.mangago.zone/read-manga/renai_kyoutei_nukegake_nashi/
The list of treesome - http://www.mangago.zone/home/mangalist/51093/ . :-)
haha hey there comrade. not that much into yuri tho... and there's a lot of BL recs already so i wanna rec a few bi love triangles. ahhh, i'm so glad to be able to rec a hodge podge of my faves without a care for (sexual) preferences haha, so refreshing
http://www.mangago.zone/read-manga/chouka_kou/ gender bender, intelligent princess pretended to be some girl's husband to save her (i kinda ship them but she's currently being paired to the enemy state's prince). historical + action
http://www.mangago.zone/read-manga/kanojo_ni_naru_hi_another/ (spin off of a fun fantasy transgender manga) bi love triangle
http://www.mangago.zone/read-manga/himegoto_juukyuusai_no_seifuku/ one of the best psychological manga with prostitution and angst. bi love triangle
http://www.mangago.zone/read-manga/seijou_kouchakan_no_jijou/ not much plot but everything you need, with good enough fanservice *leers
http://www.mangago.zone/read-manga/shitsurakuen/ my fave yuri fantasy+action. i seriously ship her with the guy... it's frustrating but still good.
http://www.mangago.zone/read-manga/bond_z/ first story. both had gfs so love polygon? (and the girls were even friends). it's hot. and i like the story. there's some raw animalism, forbidden yet exciting in their relationship
http://www.mangago.zone/read-manga/ng_life/ one of my fave manga. reincarnation so that put him in a bind, being a straight guy since he's stuck in this weird triangle of swapped gender bet. his fiancee and bestfriend. lots of interesting introspection if you read later.
unfortunately the H with YAOI mangas (the really raunchy ones) are not in this site but they do exist. :) and a lot of them are pwps anyway so these are the ones that i manage to recall out of my bi-oriented faves
(damn in the end i'm gonna make a list out of this just to save my recs haha)
also how could i forget? (love polygon, group sex. they love one girl. i was so wishing there was even one single chapter of them doing yuka grr)
http://www.mangago.zone/read-manga/thirsty_for_love/
hopefully they also have some good plot. Open to any type yaoi, shojo, yuri etc... (the joys of being bisexual ╮( ̄▽ ̄)╭)