Responses
http://www.mangago.me/read-manga/katekyo_hitman_reborn/
http://www.mangago.me/read-manga/crying_freeman/
http://www.mangago.me/read-manga/sanctuary/
http://www.mangago.me/read-manga/ouroboros/
http://www.mangago.me/read-manga/gangsta/
http://www.mangago.me/read-manga/jesus/ Has gangs in it but doesn't really focus on the gangs
http://www.mangago.me/read-manga/wild_ones/
Can someone give me a list of non-yaoi mafia/mob manga? :)