Games like The Mare Show
Games like The Mare Show include Outlast, Poppy Playtime, SOMA, Resident Evil Village, and Resident Evil 7 Biohazard. We matched them by the tags players give The Mare Show on Steam (Horror, Singleplayer, Action, Atmospheric, and First-Person): closest matches first, and among equally close ones the better-known games.

Outlast
Shared: Horror · First-Person · Atmospheric

Poppy Playtime
Shared: Horror · Singleplayer · First-Person

SOMA
Shared: Horror · Atmospheric · Psychological Horror

Resident Evil Village
Shared: Horror · Singleplayer · Action

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

Outlast 2
Shared: Horror · Singleplayer · First-Person

Five Nights at Freddy's: Security Breach
Shared: Horror · Singleplayer · First-Person

Lethal Company
Shared: Horror · First-Person · Exploration

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

Ultimate Custom Night
Shared: Horror · Singleplayer · First-Person

Bendy and the Dark Revival
Shared: Horror · Singleplayer · Action

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

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

Slender: The Arrival
Shared: Horror · First-Person · Singleplayer

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

The Beast Inside
Shared: Horror · First-Person · Action

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

The Forest
Shared: Horror · Action · First-Person

Darkwood
Shared: Horror · Action · Survival Horror

Amnesia: The Dark Descent
Shared: Horror · Atmospheric · First-Person

Five Nights at Freddy's: Sister Location
Shared: Horror · Singleplayer · First-Person

Amnesia: The Bunker
Shared: Horror · Atmospheric · Singleplayer

Five Nights at Freddy's 4
Shared: Horror · Singleplayer · First-Person

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