Another is 'Hellboy' by Mike Mignola. It has a unique take on horror with its demonic protagonist. Hellboy battles all sorts of supernatural creatures. The art style is dark and moody, which really adds to the horror atmosphere. It also has a lot of interesting mythology and backstories built into it.
One great one is 'The Walking Dead' by Robert Kirkman. It has a great mix of horror elements like zombies and the struggle for survival in a post - apocalyptic world. The characters are well - developed and the art is very effective in creating a sense of dread.