This next suggestion is not like something from the darkest, forgotten corners of YouTube kinda obscure but for a film that had a mainstream release I don't think it's very well known. It did receive a lot of critical acclaim:
It's a foreign language adult's stop-motion animation film that draws directly from the story of Colonia Dignidad in Chile.
If you haven't heard about Colonia Dignidad and you're interested, I can bring you up to speed on the backstory (there's benefits to watching it both with that foreknowledge and without it though.)
This next suggestion is not like something from the darkest, forgotten corners of YouTube kinda obscure but for a film that had a mainstream release I don't think it's very well known. It did receive a lot of critical acclaim:
The Wolf House
It's a foreign language adult's stop-motion animation film that draws directly from the story of Colonia Dignidad in Chile.
If you haven't heard about Colonia Dignidad and you're interested, I can bring you up to speed on the backstory (there's benefits to watching it both with that foreknowledge and without it though.)