Games like Pollen
Games like Pollen include Outlast, Five Nights at Freddy's: Security Breach, SOMA, Firewatch, and Five Nights at Freddy's: Secret of the Mimic. We matched them by the tags players give Pollen on Steam (Horror, Atmospheric, Exploration, Stealth, and Souls-like): closest matches first, and among equally close ones the better-known games.

Outlast
Shared: Horror · Atmospheric · First-Person

Five Nights at Freddy's: Security Breach
Shared: Horror · Stealth · Exploration

SOMA
Shared: Horror · Atmospheric · Exploration

Firewatch
Shared: Atmospheric · Exploration · First-Person

Five Nights at Freddy's: Secret of the Mimic
Shared: Horror · First-Person · Exploration

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

Little Nightmares
Shared: Horror · Atmospheric · Dark

What Remains of Edith Finch
Shared: Atmospheric · Exploration · First-Person

Lethal Company
Shared: Horror · Exploration · First-Person

Thief
Shared: Stealth · First-Person · Atmospheric

Amnesia: A Machine For Pigs
Shared: Horror · Atmospheric · Exploration

Still Wakes the Deep
Shared: Horror · Atmospheric · First-Person

Little Nightmares II
Shared: Horror · Atmospheric · Dark

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

Among the Sleep - Enhanced Edition
Shared: Horror · Atmospheric · First-Person

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

Species: Unknown
Shared: Horror · Atmospheric · Exploration

R.E.P.O.
Shared: Horror · Stealth · First-Person

Amnesia: The Bunker
Shared: Horror · Atmospheric · Stealth

Scanner Sombre
Shared: Horror · Exploration · Atmospheric

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

METRO 2033 Redux
Shared: Atmospheric · Horror · Stealth

The Forest
Shared: Horror · Exploration · First-Person

ROUTINE
Shared: Atmospheric · Horror · Dark