Atmospheric, gritty movies

I recently watched Deliverance (1972), Straw Dogs (1971) and Texas Chainsaw Massacre (1974) andn absolutely loved the three of them. That slimy atmosphere, magnetic/gray characters, atmospheric to the bone and violent, of course.

Most 70s movies i've seen are like that but the age of a movie doesn't matter too much. I was wondering maybe the names of some transgressive, violent and smart movies, and some directors to maybe look into that fit the bill.

Scorsese is my favorite director and i've seen his movies multiple times, but i've heard of Robert Altman and Sam Peckinpah (which directed Straw Dogs), so i wonder if that's the way i should go.

I like American and foreign cinema, doesn't really matter as long as it is good.

Suggestions?