Poe is awesome. If you're near Charleston, it's worth visiting Sullivan's Island- try to find the tree.

When Poe writes about murder, it's often first person point of view of the murderer- I find it more disturbing than later horror writers like HP Lovecraft or Steven King.

The Cask of Amontillado is great for that. And the classic poem The Raven describes existential dread so well.

I found with King the scarier aspects were the more mundane and psychological parts of his writing. I also found in some cases the adaptations to be better in some ways -- The Shawshank Redemption adaptation is great. And the poem in the TV adaptation of The Tommy Knockers felt more impactful than the one in the book.