Games like Fear of The Unknown
Games like Fear of The Unknown include Poppy Playtime, Outlast, Escape the Backrooms, The Beast Inside, and Outlast 2. We matched them by the tags players give Fear of The Unknown on Steam (Indie, Horror, Psychological Horror, Action, and Adventure): closest matches first, and among equally close ones the better-known games.

Poppy Playtime
Shared: Horror · Singleplayer · Psychological Horror

Outlast
Shared: Horror · Psychological Horror · First-Person

Escape the Backrooms
Shared: Horror · Psychological Horror · Adventure

The Beast Inside
Shared: Horror · Adventure · Action

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

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

Resident Evil 7 Biohazard
Shared: Horror · Singleplayer · Psychological Horror

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

Dark Deception
Shared: Horror · Psychological Horror · Indie

Resident Evil Village
Shared: Horror · Action · Singleplayer

Ready or Not
Shared: Horror · Psychological Horror · Singleplayer

Little Nightmares II
Shared: Horror · Adventure · Psychological Horror

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

Spooky's Jump Scare Mansion: HD Renovation
Shared: Indie · Horror · Adventure

Atomic Heart
Shared: Adventure · Action · Horror

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

Bendy and the Ink Machine
Shared: Horror · Indie · Singleplayer

Maid of Sker
Shared: Horror · Action · Adventure

We Happy Few
Shared: Adventure · Action · Indie

Buckshot Roulette
Shared: Horror · Indie · First-Person

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

Phasmophobia
Shared: Horror · Psychological Horror · First-Person

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

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