Horror
Horror novels can overlap with several other genres (particularly fantasy and thriller), but what sets the horror genre apart is that the point is to scare the reader and set them ill at ease. The plot can involve either real-world or supernatural horror.
Try some of these authors: Bram Stoker, Mary Shelley, Stephen King, Joe Hill, Jim Butcher, Max Brooks, Riley Sager, Shirley Jackson, Anne Rice, Dean Koontz, Alma Katsu, Grady Hendrix
The Haunting of Hill House by Shirley Jackson
The Only Good Indians by Stephen Graham Jones
Mexican Gothic by Silvia Moreno-Garcia
Survive the Night by Riley Sager
The Final Girl Support Group by Grady Hendrix
The Southern Book Club's Guide to Slaying Vampires by Grady Hendrix
The Institute by Stephen King
Cujo by Stephen King
Home Before Dark by Riley Sager
Lock Every Door by Riley Sager
The Hunger by Alma Katsu
Full Throttle by Joe Hill