Games like The Guest
Games like The Guest include Outlast, Poppy Playtime, Visage, Outlast 2, and SOMA. We matched them by the tags players give The Guest on Steam (Indie, Horror, Psychological Horror, Dark, and First-Person): closest matches first, and among equally close ones the better-known games.

Outlast
Shared: Horror · First-Person · Psychological Horror

Poppy Playtime
Shared: Horror · First-Person · Dark

Visage
Shared: Horror · Psychological Horror · Dark

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

SOMA
Shared: Horror · Psychological Horror · Dark

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

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

From The Darkness
Shared: Horror · Psychological Horror · Indie

Blair Witch
Shared: Horror · Indie · Psychological Horror

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

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

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

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

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

Little Nightmares
Shared: Horror · Adventure · Indie

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

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

Amnesia: A Machine For Pigs
Shared: Horror · Psychological Horror · Walking Simulator

Firewatch
Shared: Adventure · Atmospheric · First-Person

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

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

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

Mouthwashing
Shared: Horror · Psychological Horror · Indie

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