You might enjoy Nazareth Hill by Ramsey Campbell. It's an excellent psychological horror novel. It's a slow-burn story, becoming increasingly unsettling as it goes along, and it sticks the landing.

For a great mystery novel, try The Far Cry by Fredric Brown. It was originally published in the 1950s, and it has an ending that I didn't see coming at all, while still making sense and not coming out of nowhere.

For an alien invasion story that is not cliche, try Agents of Dreamland by Caitlin R. Kiernan. It's a short novel, about 130 pages. It's a standalone, but there is a follow-up novel called Black Helicopters, and a third one is being released later this year.