I’m really more a SFF and Speculative Ficton guy but last year I read Sister, Maiden, Monster by Lucy A. Snyder. It was great. In one word, viceral.

Frankenstein by Mary Shelly is kind of a must read imo. It’s credited as the first sci-fi book but is horror in its roots I think.

And Island of Dr. Moreau is pretty scary if you can sort of put yourself in the context. I’d suggest reading The Daughter of Doctor Moreau by Silvia Moreno-Garca after that to have fun with an old story but told by not a colonizing white dude.