Games like Smile
Games like Smile include Poppy Playtime, Ultimate Custom Night, Five Nights at Freddy's 2, Five Nights at Freddy's, and Outlast. We matched them by the tags players give Smile on Steam (Indie, Strategy, Horror, First-Person, and Singleplayer): closest matches first, and among equally close ones the better-known games.

Poppy Playtime
Shared: Horror · Singleplayer · First-Person

Ultimate Custom Night
Shared: Horror · Singleplayer · Strategy

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

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

Outlast
Shared: Horror · First-Person · Survival Horror

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

Five Nights at Freddy's 3
Shared: Horror · Singleplayer · First-Person

Buckshot Roulette
Shared: Horror · Strategy · First-Person

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

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

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

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

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

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

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

Pacify
Shared: Horror · Survival Horror · First-Person

Dark Deception
Shared: Horror · First-Person · Singleplayer

SOMA
Shared: Horror · Psychological Horror · Survival Horror

MiSide
Shared: Horror · First-Person · Psychological Horror

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

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

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

Granny
Shared: Horror · Survival Horror · First-Person