Games like Terra Firma 2
Games like Terra Firma 2 include Universe Sandbox, Totally Accurate Battle Simulator, Kerbal Space Program, Planet Coaster, and Garry's Mod. We matched them by the tags players give Terra Firma 2 on Steam (Simulation, Sandbox, Indie, God Game, and Physics): closest matches first, and among equally close ones the better-known games.

Universe Sandbox
Shared: Simulation · Sandbox · Physics

Totally Accurate Battle Simulator
Shared: Simulation · Sandbox · Physics

Kerbal Space Program
Shared: Simulation · Sandbox · Physics

Planet Coaster
Shared: Simulation · Sandbox · Relaxing

Garry's Mod
Shared: Sandbox · Physics · Simulation

People Playground
Shared: Sandbox · Physics · Simulation

Reus
Shared: Simulation · God Game · Indie

BeamNG.drive
Shared: Simulation · Physics · Sandbox

Equilinox
Shared: Simulation · Indie · Sandbox

House Flipper
Shared: Simulation · Singleplayer · Sandbox

Cities: Skylines II
Shared: Simulation · Sandbox · Singleplayer

Space Engineers
Shared: Sandbox · Simulation · Physics

Poly Bridge
Shared: Simulation · Physics · Sandbox

WorldBox - God Simulator
Shared: Sandbox · Simulation · God Game

Teardown
Shared: Sandbox · Physics · Indie

Planet Coaster 2
Shared: Simulation · Sandbox · Singleplayer

Mountain
Shared: Simulation · Indie · Singleplayer

Goat Simulator
Shared: Simulation · Sandbox · Physics

Paralives
Shared: Simulation · Indie · Sandbox

Planet Zoo
Shared: Simulation · Sandbox · Nature

Townscaper
Shared: Sandbox · Relaxing · Simulation

Cities: Skylines
Shared: Simulation · Sandbox · Singleplayer

Universe Sandbox
Shared: Simulation · Sandbox · Physics

Brick Rigs
Shared: Sandbox · Simulation · Physics