Games like Project Third Eye
Games like Project Third Eye include Hot Dogs, Horseshoes & Hand Grenades, Garry's Mod, BONEWORKS, Blade and Sorcery, and Kerbal Space Program. We matched them by the tags players give Project Third Eye on Steam (Sandbox, Programming, Physics, Moddable, and Action): closest matches first, and among equally close ones the better-known games.

Hot Dogs, Horseshoes & Hand Grenades
Shared: Sandbox · VR · Physics

Garry's Mod
Shared: Sandbox · Moddable · Physics

BONEWORKS
Shared: VR · Sandbox · Physics

Blade and Sorcery
Shared: VR · Sandbox · Moddable

Kerbal Space Program
Shared: Sandbox · Physics · Moddable

BONELAB
Shared: VR · Sandbox · Physics

BeamNG.drive
Shared: Physics · Sandbox · Simulation

Hard Bullet
Shared: VR · Sandbox · Action

People Playground
Shared: Sandbox · Physics · Moddable

CarX Drift Racing Online
Shared: Sandbox · Moddable · Physics

Beyond Sandbox
Shared: Sandbox · VR · Physics

Totally Accurate Battle Simulator
Shared: Sandbox · Physics · Simulation

Ravenfield
Shared: Sandbox · Action · Shooter

Skater XL - The Ultimate Skateboarding Game
Shared: Sandbox · Skateboarding · Physics

Tabletop Simulator
Shared: Sandbox · VR · Moddable

Universe Sandbox
Shared: Sandbox · Physics · Simulation

Besiege
Shared: Sandbox · Physics · Moddable

Space Engineers
Shared: Sandbox · Physics · Moddable

Ancient Warfare 3
Shared: Sandbox · Action · Moddable

Car Mechanic Simulator 2021
Shared: Sandbox · Moddable · Simulation

BRUTALISTICK VR
Shared: VR · Sandbox · Physics

Endorphin Vice
Shared: Sandbox · Physics · Action

while True: learn()
Shared: Programming · Sandbox · Education

GoreBox
Shared: Sandbox · Physics · Shooter