Games like Flat Earth Simulator
Games like Flat Earth Simulator include Internet Cafe Simulator 2, BABBDI, Outer Wilds, The Long Dark, and POOLS. We matched them by the tags players give Flat Earth Simulator on Steam (Experimental, Exploration, 3D, Conspiracy, and Atmospheric): closest matches first, and among equally close ones the better-known games.

Internet Cafe Simulator 2
Shared: Exploration · 3D · Simulation

BABBDI
Shared: Exploration · Atmospheric · Surreal

Outer Wilds
Shared: Exploration · Atmospheric · Space

The Long Dark
Shared: Exploration · Atmospheric · Singleplayer

POOLS
Shared: Exploration · Atmospheric · Surreal

Kerbal Space Program
Shared: Simulation · Space · Education

nophenia
Shared: Exploration · Atmospheric · Surreal

Firewatch
Shared: Atmospheric · Exploration · Singleplayer

Moncage
Shared: Atmospheric · Experimental · Surreal

The Looker
Shared: Exploration · 3D · Atmospheric

Ultimate Fishing Simulator
Shared: 3D · Simulation · Exploration

Exo One
Shared: Exploration · Atmospheric · Space

No Man's Sky
Shared: Exploration · Space · Atmospheric

X4: Foundations
Shared: Exploration · Simulation · Space

PC Building Simulator
Shared: Simulation · Education · 3D

Dreamcore
Shared: Exploration · 3D · Surreal

PEAK
Shared: Exploration · 3D · Atmospheric

Manifold Garden
Shared: Exploration · Surreal · Experimental

What Remains of Edith Finch
Shared: Atmospheric · Exploration · Walking Simulator

Crime Scene Cleaner
Shared: Simulation · Atmospheric · Singleplayer

Stellaris
Shared: Exploration · Space · Simulation

The Exit 8
Shared: Exploration · 3D · Walking Simulator

Fireworks Mania - An Explosive Simulator
Shared: Exploration · 3D · Singleplayer

COCOON
Shared: Exploration · Atmospheric · 3D