Games like The 31st Student
Games like The 31st Student include What Remains of Edith Finch, Firewatch, SOMA, Outer Wilds, and Layers of Fear (2016). We matched them by the tags players give The 31st Student on Steam (Psychological Horror, Horror, Exploration, Mystery, and Atmospheric): closest matches first, and among equally close ones the better-known games.

What Remains of Edith Finch
Shared: Atmospheric · Mystery · Exploration

Firewatch
Shared: Atmospheric · Adventure · Mystery

SOMA
Shared: Psychological Horror · Horror · Atmospheric

Outer Wilds
Shared: Exploration · Mystery · Atmospheric

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

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

Phasmophobia
Shared: Horror · Psychological Horror · First-Person

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

The Painscreek Killings
Shared: Mystery · Exploration · Horror

Inside the Backrooms
Shared: Horror · Psychological Horror · Exploration

MiSide
Shared: Psychological Horror · Horror · Story Rich

Mouthwashing
Shared: Psychological Horror · Horror · Atmospheric

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

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

Poppy Playtime
Shared: Horror · Psychological Horror · First-Person

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

The Vanishing of Ethan Carter
Shared: Mystery · Atmospheric · Exploration

INFRA
Shared: Exploration · Atmospheric · First-Person

The Forgotten City
Shared: Exploration · Mystery · Adventure

Outlast
Shared: Horror · Psychological Horror · First-Person

Scanner Sombre
Shared: Exploration · Horror · Psychological Horror

The Park®
Shared: Psychological Horror · Horror · First-Person

Dagon: by H. P. Lovecraft
Shared: Horror · Atmospheric · Psychological Horror

Blue Prince
Shared: Exploration · Mystery · Investigation