Games like The Maze Project
Games like The Maze Project include Phasmophobia, SOMA, Sally Face - Episode One, Poppy Playtime, and Inside the Backrooms. We matched them by the tags players give The Maze Project on Steam (Horror, Psychological Horror, Dark, Atmospheric, and Supernatural): closest matches first, and among equally close ones the better-known games.

Phasmophobia
Shared: Horror · Psychological Horror · Supernatural

SOMA
Shared: Horror · Psychological Horror · Atmospheric

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

Poppy Playtime
Shared: Horror · Dark · Psychological Horror

Inside the Backrooms
Shared: Horror · Psychological Horror · Atmospheric

Pacify
Shared: Horror · Psychological Horror · Dark

What Remains of Edith Finch
Shared: Atmospheric · Mystery · Story Rich

Little Nightmares II
Shared: Horror · Dark · Psychological Horror

Layers of Fear (2016)
Shared: Horror · Psychological Horror · Atmospheric

Outlast
Shared: Horror · Psychological Horror · Atmospheric

Outer Wilds
Shared: Exploration · Mystery · Atmospheric

Amnesia: A Machine For Pigs
Shared: Horror · Atmospheric · Psychological Horror

MiSide
Shared: Psychological Horror · Horror · Atmospheric

Little Nightmares
Shared: Horror · Atmospheric · Dark

Mouthwashing
Shared: Horror · Psychological Horror · Atmospheric

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

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

Outlast 2
Shared: Horror · Psychological Horror · Dark

Darkwood
Shared: Horror · Psychological Horror · Dark

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

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

Firewatch
Shared: Atmospheric · Mystery · Story Rich

Escape the Backrooms
Shared: Horror · Psychological Horror · Exploration

Still Wakes the Deep
Shared: Horror · Psychological Horror · Dark