Start with high-confidence psychological horror books, then narrow by subgenre or adjacent topics.
A Head Full of Ghosts
Paul Tremblay
Pretty Girls
Karin Slaughter
All the Dead Lie Down
Kyrie McCauley
The Devouring Light
Kat Ellis
The Ghost Women
Jennifer Murphy
They Fear Not Men in the Woods
Gretchen McNeil, Justis Bolding
No Rest for the Wicked
Rachel Louise Adams, Jeremy Carlisle Parker
Dead Girls Don't Dream
Nino Cipri
May the Dead Keep You
Jill Baguchinsky
Hidden Pictures
Jason Rekulak
Gorgeous Gruesome Faces
Linda Cheng
Ghost Night
Heather Graham
Confessions of the Dead
James Patterson, J. D. Barker
Night Watcher
Daphne Woolsoncroft, Helen Laser
Maniac
Harold Schechter, Braden Wright
The Country Will Bring US No Peace
Matthieu Simard, Pablo Strauss
Her Hunger
John Shirley
The Bog Wife
Kay Chronister, Shannon McManus
Fruit of the Flesh
I.V. Ophelia
On Sundays She Picked Flowers
Yah Yah Scholfield, Angel Pean
Ghost Eaters
Clay Chapman, Clay McLeod Chapman
Apt Pupil
Stephen King
The Corpse Queen
Heather M. Herrman
Ghosts of the Silent Hills
Anita Krishan