Aha! My field of expertise! Here’s some people don’t talk about often, most of which cost very little and offer very much.

Chilla’s Art games. Start with Closing Shift, The Bathhouse, and Shinkansen 0. Shinkansen 0 is an excellent game but less spooky than the others. The Radio Station is also pretty good, but the driving got arduous to me.

Devotion you can get from Red Candle Games’ website, DRM free. Doable in a day, excellent experience.

Penumbra games predate Amnesia, they’re quite spooky!

The Exit 8. Similar to Shinkansen 0, would absolutely recommend.

Missing Hiker. Very atmosphere.