Games like たんぼ
Games like たんぼ include Firewatch, The Stanley Parable, Five Nights at Freddy's: Security Breach, What Remains of Edith Finch, and Layers of Fear (2016). We matched them by the tags players give たんぼ on Steam (Walking Simulator, Adventure, Singleplayer, Horror, and Psychological): closest matches first, and among equally close ones the better-known games.

Firewatch
Shared: Adventure · Walking Simulator · Singleplayer

The Stanley Parable
Shared: Walking Simulator · Psychological · Adventure

Five Nights at Freddy's: Security Breach
Shared: Singleplayer · Horror · Adventure

What Remains of Edith Finch
Shared: Walking Simulator · Adventure · Singleplayer

Layers of Fear (2016)
Shared: Walking Simulator · Horror · Singleplayer

The Exit 8
Shared: Walking Simulator · Exploration · Horror

Blair Witch
Shared: Adventure · Horror · Walking Simulator

Valley
Shared: Adventure · Singleplayer · Exploration

The Park®
Shared: Walking Simulator · Horror · Singleplayer

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

Scanner Sombre
Shared: Walking Simulator · Horror · Adventure

Subnautica
Shared: Horror · Singleplayer · Exploration

The Beginner's Guide
Shared: Walking Simulator · Singleplayer · Adventure

The Forest
Shared: Horror · Adventure · First-Person

Slime Rancher
Shared: Adventure · Singleplayer · Exploration

The Beast Inside
Shared: Adventure · Horror · Singleplayer

INFRA
Shared: Walking Simulator · Exploration · Adventure

The Long Dark
Shared: Singleplayer · Exploration · Adventure

Poppy Playtime
Shared: Singleplayer · Horror · First-Person

Among the Sleep - Enhanced Edition
Shared: Horror · Adventure · Walking Simulator

Kona
Shared: Adventure · Singleplayer · Walking Simulator

Subnautica: Below Zero
Shared: Singleplayer · Horror · Exploration

Still Wakes the Deep
Shared: Horror · Walking Simulator · Adventure

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