Good movies about demented families?

I’m a horror fan, so one might know what I have in mind for this question. I am quite familiar with The Texas Chain Saw Massacre series, originals and remakes.
The Wrong Turn movies as well, and anything Rob Zombie makes. I am left wanting for more. Horror movies that center around demented, psychotic killer families.

However, drama or suspense movies about that same subject, and which may be a little more high brow than the general horror formula, are welcome too.

One slight specification I have is, please, no movies with super powers or ghosts or zombies did I just say that or demons. However, the occult, religion and the like are welcome.

Shoot. What do you have? Any gems? If possible, please include a short description of the movie, as well. One of my joys in anticipating a movie is to never watch the trailer. Thanks.