So many many examples, especially when you obviously delve into the world of Doris Wishman, the Something Weird Video catalog, etc. Virtually a bottomless pit.
Anyways - some Italian favorites that never get enough attention:
BLUE MOVIE (1978) dir. Alberto Cavallone
MAN, WOMAN, BEAST (1977) dir. Alberto Cavallone
QUANDO L'AMORE E OSCENITA (1980) dir. Renato Polselli
Plus - I think my favorite film hands down that tackles so many themes of De Sade's ideology, fetishism, etc. in a such a VIVID and descriptive way, even eventually horrifyingly is:
JUSTINE DE SADE (1972) dir. Claude Pierson
Actually almost captures the sheer chaos of a De Sade book.