These are the iconic gangsters movies that really change the game for crime cinema, all those are iconic crime films, all the Mob films & crime movies in one list
Mafia / Gangster Related Collection
https://en.wikipedia.org/wiki/List_of_films_based_on_actual_events
Best Mafia Movies of all time.
Crime Film Collection
My favourite Gangster movies
Cosa Nostra, Bloods, Crips and Mexican Mafia Mob Movies
A Collection of Mob Movies. Ranked in order of amazingness. Ones I haven't seen yet will be on here too, but at the bottom.
Crime
by J. Petersson