Games like The Green Light
Games like The Green Light include Mouthwashing, What Remains of Edith Finch, Firewatch, Sally Face - Episode One, and No, I'm not a Human. We matched them by the tags players give The Green Light on Steam (Horror, Psychological Horror, Mystery, Emotional, and Story Rich): closest matches first, and among equally close ones the better-known games.

Mouthwashing
Shared: Horror · Psychological Horror · Story Rich

What Remains of Edith Finch
Shared: Story Rich · Mystery · Walking Simulator

Firewatch
Shared: Adventure · Mystery · Story Rich

Sally Face - Episode One
Shared: Psychological Horror · Horror · Story Rich

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

Layers of Fear (2016)
Shared: Horror · Psychological Horror · Story Rich

Amnesia: A Machine For Pigs
Shared: Horror · Story Rich · Psychological Horror

SOMA
Shared: Horror · Psychological Horror · Story Rich

MiSide
Shared: Psychological Horror · Horror · Story Rich

Poppy Playtime
Shared: Horror · Psychological Horror · Mystery

Blair Witch
Shared: Horror · Psychological Horror · Adventure

Still Wakes the Deep
Shared: Horror · Psychological Horror · Story Rich

SILENT HILL 2
Shared: Horror · Psychological Horror · Story Rich

Summer of '58
Shared: Horror · Psychological Horror · Walking Simulator

The Park®
Shared: Horror · Psychological Horror · Walking Simulator

DISTRAINT: Deluxe Edition
Shared: Psychological Horror · Horror · Indie

The Cat Lady
Shared: Horror · Psychological Horror · Story Rich

Fran Bow
Shared: Psychological Horror · Horror · Story Rich

Little Nightmares II
Shared: Horror · Adventure · Psychological Horror

Martha Is Dead
Shared: Psychological Horror · Horror · Story Rich

The Beginner's Guide
Shared: Story Rich · Walking Simulator · Indie

Outer Wilds
Shared: Mystery · Story Rich · Adventure

[Chillas Art] The Convenience Store
Shared: Horror · Psychological Horror · Adventure

Outlast
Shared: Horror · Psychological Horror · First-Person