Games like SOMNI
Games like SOMNI include Phasmophobia, Escape the Backrooms, R.E.P.O., Backrooms: Escape Together, and Shift At Midnight. We matched them by the tags players give SOMNI on Steam (Simulation, 3D, Horror, First-Person, and Realistic): closest matches first, and among equally close ones the better-known games.

Phasmophobia
Shared: Horror · VR · Multiplayer

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

R.E.P.O.
Shared: Horror · 3D · Multiplayer

Backrooms: Escape Together
Shared: Horror · Multiplayer · First-Person

Shift At Midnight
Shared: Horror · Simulation · 3D

Bodycam
Shared: Realistic · Horror · Multiplayer

Gorilla Tag
Shared: VR · First-Person · Horror

Farming Simulator 25
Shared: Simulation · 3D · Realistic

Pacify
Shared: Horror · Multiplayer · Online Co-Op

DEVOUR
Shared: Horror · Multiplayer · Online Co-Op

BeamNG.drive
Shared: Simulation · Realistic · Multiplayer

Dead by Daylight
Shared: Horror · Multiplayer · Online Co-Op

Demonologist
Shared: Horror · Multiplayer · First-Person

PEAK
Shared: Multiplayer · 3D · First-Person

Assetto Corsa
Shared: Simulation · VR · Multiplayer

Buckshot Roulette
Shared: Horror · Multiplayer · First-Person

City Car Driving
Shared: Simulation · Realistic · VR

The Mortuary Assistant
Shared: Horror · Simulation · Demons

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

Inside the Backrooms
Shared: Horror · Multiplayer · First-Person

Arma 3
Shared: Simulation · Multiplayer · Realistic

Fast Food Simulator
Shared: Simulation · Multiplayer · 3D

Lethal Company
Shared: Horror · First-Person · Online Co-Op

Content Warning
Shared: Horror · Online Co-Op · Multiplayer