Games like Trapped
Games like Trapped include Poppy Playtime, Firewatch, Layers of Fear (2016), What Remains of Edith Finch, and Outlast. We matched them by the tags players give Trapped on Steam (Indie, Adventure, Horror, First-Person, and Atmospheric): closest matches first, and among equally close ones the better-known games.

Poppy Playtime
Shared: Horror · Singleplayer · First-Person

Firewatch
Shared: Adventure · Atmospheric · First-Person

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

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

Outlast
Shared: Horror · First-Person · Atmospheric

Little Nightmares
Shared: Horror · Adventure · Atmospheric

The Room
Shared: Adventure · Atmospheric · Indie

The Room Two
Shared: Atmospheric · Horror · Adventure

Little Nightmares II
Shared: Adventure · Horror · Singleplayer

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

Firework
Shared: Indie · Horror · Puzzle

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

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

MiSide
Shared: Horror · Psychological Horror · First-Person

The Room Three
Shared: Adventure · Indie · Puzzle

Outer Wilds
Shared: Adventure · Atmospheric · Mystery

Among the Sleep - Enhanced Edition
Shared: Indie · Horror · Adventure

Amnesia: A Machine For Pigs
Shared: Horror · First-Person · Atmospheric

SOMA
Shared: Horror · Atmospheric · Psychological Horror

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

Blair Witch
Shared: Adventure · Horror · Indie

Rusty Lake Paradise
Shared: Indie · Adventure · Horror

INFRA
Shared: First-Person · Atmospheric · Adventure

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