Games like MOTHER
Games like MOTHER include Poppy Playtime, Outlast, No, I'm not a Human, Outlast 2, and Five Nights at Freddy's. We matched them by the tags players give MOTHER on Steam (Psychological Horror, Horror, First-Person, Singleplayer, and Dark): closest matches first, and among equally close ones the better-known games.

Poppy Playtime
Shared: Horror · Singleplayer · First-Person

Outlast
Shared: Horror · First-Person · Psychological Horror

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

Outlast 2
Shared: Psychological Horror · Horror · First-Person

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

Five Nights at Freddy's 2
Shared: Horror · Singleplayer · Psychological Horror

Mouthwashing
Shared: Psychological Horror · Horror · Indie

MiSide
Shared: Psychological Horror · Horror · First-Person

SOMA
Shared: Psychological Horror · Horror · Dark

Buckshot Roulette
Shared: Horror · Dark · First-Person

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

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

Resident Evil Village
Shared: Horror · First-Person · Singleplayer

Visage
Shared: Psychological Horror · Horror · Dark

Layers of Fear (2016)
Shared: Psychological Horror · Horror · First-Person

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

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

Dark Deception
Shared: Horror · Psychological Horror · Singleplayer

Bendy and the Dark Revival
Shared: Horror · First-Person · Singleplayer

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

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

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

Little Nightmares II
Shared: Horror · Singleplayer · Psychological Horror

Little Nightmares
Shared: Horror · Singleplayer · Dark