mafia/Yankee/delinquent manga

in eunsuk & junggu one of the main boys is yakuza affiliated and the other is just a thot(⊙…⊙ )

http://www.mangago.me/read-manga/rouge_katsura_komachi/

http://www.mangago.me/read-manga/aka_to_kuro_katsura_komachi/

http://www.mangago.me/read-manga/kemono_ni_namida/

Saezuru Tori wa Habatakanai is the best yakuza yaoi I've read (and probably one of the best yaoi in general). Also Honto Yajuu and Finder (aka Viewfinder) are pretty good

i kept it separated but i have a rec list. it's fewer than others because it is my recommendation, not an all-in list plus i have preferences
http://www.mangago.me/home/mangalist/43239/
http://www.mangago.me/home/mangalist/45872/

Read Acid Town, Saezuru Tori wa Habatakanai if you want some detailed serious shit about the yakuza world. There's Finder, Aiso Tsukashi, Kuro to Aka just to name a few.