Horror books about the occult (no Satanism please)

Hello, everybody. I'm looking for some horror books that are centered around the occult and the esoteric. However, I don't want to read anything that has Satanic elements to it, because I've always found Satanic stuff to be rather shallow and boring. My main issue with Satanic horror is the view that there is a strict dualism between good and evil. I'm looking for something a little more complex and ambiguous, like Lovecraft for example. However, I am also willing to read books that have Satan in them if the book subverts expectations about the nature of Satan, God, etc.

Also, I'm willing to read books that may center around another religion, as long as the story doesn't follow that very strict metaphysical good vs. evil storyline.