Games like UNHEIM
Games like UNHEIM include Phasmophobia, Outlast, Mouthwashing, Five Nights at Freddy's, and Poppy Playtime. We matched them by the tags players give UNHEIM on Steam (Psychological, Cinematic, Supernatural, Psychological Horror, and Horror): closest matches first, and among equally close ones the better-known games.

Phasmophobia
Shared: Horror · Psychological Horror · Supernatural

Outlast
Shared: Horror · First-Person · Psychological Horror

Mouthwashing
Shared: Psychological Horror · Horror · Psychological

Five Nights at Freddy's
Shared: Horror · Psychological Horror · Survival Horror

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

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

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

Pacify
Shared: Horror · Psychological Horror · Supernatural

SOMA
Shared: Psychological Horror · Horror · Atmospheric

SILENT HILL 2
Shared: Psychological Horror · Horror · Psychological

Summer of '58
Shared: Horror · Psychological Horror · Cinematic

Buckshot Roulette
Shared: Horror · Dark · Psychological

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

Five Nights at Freddy's 2
Shared: Horror · Psychological Horror · First-Person

Amnesia: The Dark Descent
Shared: Horror · Psychological Horror · Atmospheric

Garten of Banban
Shared: Horror · Psychological Horror · First-Person

Visage
Shared: Psychological Horror · Horror · First-Person

Lost in Vivo
Shared: Psychological Horror · Horror · Psychological

Backrooms: Escape Together
Shared: Horror · Psychological Horror · Atmospheric

The Outlast Trials
Shared: Horror · Psychological Horror · First-Person

DEVOUR
Shared: Horror · Psychological Horror · Survival Horror

The Mortuary Assistant
Shared: Supernatural · Horror · Atmospheric

Inside the Backrooms
Shared: Horror · Psychological Horror · Survival Horror

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