Games like The Mortuary Assistant
Games like The Mortuary Assistant include Phasmophobia, Poppy Playtime, Firewatch, Outlast, and Ghostwire: Tokyo. We matched them by the tags players give The Mortuary Assistant on Steam (Horror, Supernatural, Demons, Mystery, and Atmospheric): closest matches first, and among equally close ones the better-known games.

Phasmophobia
Shared: Horror · Supernatural · Multiplayer

Poppy Playtime
Shared: Horror · Singleplayer · Mystery

Firewatch
Shared: Atmospheric · Mystery · Singleplayer

Outlast
Shared: Horror · Atmospheric · First-Person

Ghostwire: Tokyo
Shared: Supernatural · Horror · Singleplayer

Pacify
Shared: Horror · Supernatural · Multiplayer

Buckshot Roulette
Shared: Horror · Multiplayer · Singleplayer

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

What Remains of Edith Finch
Shared: Atmospheric · Mystery · Singleplayer

Visage
Shared: Horror · Singleplayer · Atmospheric

Demonologist
Shared: Horror · Demons · Multiplayer

Ghost Exorcism INC.
Shared: Horror · Supernatural · Atmospheric

Firework
Shared: Horror · Mystery · Atmospheric

Five Nights at Freddy's
Shared: Horror · Singleplayer · Indie

The Room
Shared: Mystery · Atmospheric · Singleplayer

Sally Face - Episode One
Shared: Horror · Mystery · Atmospheric

Little Nightmares II
Shared: Horror · Singleplayer · Atmospheric

Little Nightmares
Shared: Horror · Atmospheric · Singleplayer

Outer Wilds
Shared: Mystery · Atmospheric · Singleplayer

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

Bendy and the Ink Machine
Shared: Horror · Singleplayer · First-Person

The Room Two
Shared: Mystery · Horror · Atmospheric

Murdered: Soul Suspect
Shared: Supernatural · Horror · Mystery

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