Games like Eight
Games like Eight include SOMA, Outlast, Still Wakes the Deep, Mouthwashing, and No, I'm not a Human. We matched them by the tags players give Eight on Steam (Horror, Psychological Horror, Interactive Fiction, First-Person, and Indie): closest matches first, and among equally close ones the better-known games.

SOMA
Shared: Horror · Psychological Horror · Story Rich

Outlast
Shared: Horror · First-Person · Psychological Horror

Still Wakes the Deep
Shared: Horror · Psychological Horror · First-Person

Mouthwashing
Shared: Horror · Psychological Horror · Story Rich

No, I'm not a Human
Shared: Horror · Psychological Horror · Indie

Amnesia: A Machine For Pigs
Shared: Horror · Psychological Horror · First-Person

Outlast 2
Shared: Horror · Psychological Horror · First-Person

MiSide
Shared: Psychological Horror · Horror · First-Person

Layers of Fear (2016)
Shared: Horror · Psychological Horror · First-Person

Sally Face - Episode One
Shared: Psychological Horror · Horror · Indie

Amnesia: The Dark Descent
Shared: Horror · Psychological Horror · First-Person

Lethal Company
Shared: Horror · First-Person · Psychological Horror

Poppy Playtime
Shared: Horror · First-Person · Psychological Horror

Escape the Backrooms
Shared: Horror · Psychological Horror · First-Person

Visage
Shared: Horror · Psychological Horror · First-Person

The Beast Inside
Shared: Horror · First-Person · Psychological Horror

What Remains of Edith Finch
Shared: Story Rich · First-Person · Exploration

Fran Bow
Shared: Psychological Horror · Horror · Story Rich

Ready or Not
Shared: Horror · Realistic · Psychological Horror

Resident Evil 7 Biohazard
Shared: Horror · First-Person · Psychological Horror

Tiny Bunny
Shared: Horror · Psychological Horror · Story Rich

Buckshot Roulette
Shared: Horror · First-Person · Indie

Firewatch
Shared: First-Person · Story Rich · Adventure

Blair Witch
Shared: Horror · Psychological Horror · First-Person