My favorite genre in fiction is horror, and these are my favorites within the genre (that I've read so far). I have a particular taste for genre-blends (ie. sci-fi horror, dystopian horror, fantasy horror...), Gothic works, folk horror, haunted places, conceptual scares, freaky occult stuff, etc. Also these are listed in chronological order by release date, so that it's almost like a truncated history of horror :)
Disclaimers: No, I haven't read House of Leaves yet, (though I plan to, because I think I'll love it). Also, Carrie is the only Stephen King book on here because I hate his writing style in literally everything else I've tried to read from him. (I'm also really not a fan of writers like Joe Hill or Grady Hendrix). So if those are the kinds of horror books you're into, these recs will probably not be to your taste.
The Lottery and Other Stories by Shirley Jackson
The October Country by Ray Bradbury
The Haunting of Hill House by Shirley Jackson
White is for Witching by Helen Oyeyemi
Mouthful of Birds by Samanta Schweblin
Frankenstein in Baghdad by Ahmed Saadawi
Annihilation by Jeff VanderMeer
Things We Lost in the Fire by Mariana Enriquez
Jawbone by Monica Ojeda
In the House in the Dark of the Woods by Laird Hunt
Our Share of Night by Mariana Enriquez
Bunny by Mona Awad
If you're interested, you can find non-fiction & scholarly work on the horror genre in this subject guide.