Games like The Anomaly Project
Games like The Anomaly Project include Escape the Backrooms, Phasmophobia, PEAK, Backrooms: Escape Together, and Lethal Company. We matched them by the tags players give The Anomaly Project on Steam (Online Co-Op, Horror, Psychological Horror, Multiplayer, and First-Person): closest matches first, and among equally close ones the better-known games.

Escape the Backrooms
Shared: Horror · Online Co-Op · Multiplayer

Phasmophobia
Shared: Online Co-Op · Horror · Psychological Horror

PEAK
Shared: Online Co-Op · Multiplayer · Co-op

Backrooms: Escape Together
Shared: Horror · Online Co-Op · Multiplayer

Lethal Company
Shared: Online Co-Op · Horror · Co-op

Pacify
Shared: Online Co-Op · Horror · Multiplayer

Inside the Backrooms
Shared: Horror · Multiplayer · Psychological Horror

Fears to Fathom® - Scratch Creek
Shared: Horror · Psychological Horror · Multiplayer

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

R.E.P.O.
Shared: Online Co-Op · Horror · Multiplayer

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

RV There Yet?
Shared: Online Co-Op · Multiplayer · Co-op

Demonologist
Shared: Horror · Online Co-Op · Multiplayer

DEVOUR
Shared: Online Co-Op · Horror · Multiplayer

Nuclear Nightmare
Shared: Online Co-Op · Horror · Co-op

How to Fish
Shared: Online Co-Op · Multiplayer · Co-op

We Were Here
Shared: Co-op · Horror · Multiplayer

Subnautica 2
Shared: Horror · Multiplayer · Co-op

Left 4 Dead 2
Shared: Co-op · Online Co-Op · Multiplayer

Labyrinthine
Shared: Online Co-Op · Horror · Multiplayer

The Outlast Trials
Shared: Horror · Multiplayer · Psychological Horror

Zort
Shared: Online Co-Op · Horror · Psychological Horror

PANICORE
Shared: Online Co-Op · Horror · Psychological Horror

Lunch Lady
Shared: Online Co-Op · Horror · Multiplayer