Be it Lemmy, Mastodon, or some other instance on some other service.
DragonsFuckingCars is literally crude drawings, illustrations, animations, and 3D renders of dragons having literal intercourse with cars.
Spacedicks. I don’t even know if that sub still exists. I’m not even searching if it is.
But, there was like really graphic, NSFL gore and weird Porn on there. I remember one was the aftermath of a teen in Brazil that kicked a bus tire and it blew off his leg and he was just agonizing on the floor, with bone and flesh dangling from whatever was left of his shin. And that was one of the “mild” ones.