Games like Tumblefire
Games like Tumblefire include Teardown, Thief Simulator, Black Desert, Tainted Grail: The Fall of Avalon, and Goat Simulator 3. We matched them by the tags players give Tumblefire on Steam (Heist, Western, Stealth, Exploration, and Physics): closest matches first, and among equally close ones the better-known games.

Teardown
Shared: Physics · Heist · Sandbox

Thief Simulator
Shared: Stealth · Heist · Simulation

Black Desert
Shared: Exploration · Action RPG · Sandbox

Tainted Grail: The Fall of Avalon
Shared: Exploration · Character Customization · RPG

Goat Simulator 3
Shared: Physics · Exploration · Character Customization

Kenshi
Shared: Sandbox · Immersive Sim · RPG

BeamNG.drive
Shared: Physics · Simulation · Sandbox

Monster Hunter: World
Shared: Character Customization · Action · Action RPG

PEAK
Shared: Physics · Exploration · Character Customization

Totally Accurate Battle Simulator
Shared: Physics · Sandbox · Simulation

PAYDAY 2
Shared: Heist · Stealth · Action

Fallout: New Vegas
Shared: Exploration · Western · RPG

Goat Simulator
Shared: Physics · Sandbox · Simulation

People Playground
Shared: Physics · Sandbox · Destruction

Hogwarts Legacy
Shared: Exploration · Character Customization · RPG

The Elder Scrolls IV: Oblivion Remastered
Shared: Exploration · Character Customization · Action RPG

鬼谷八荒 Tale of Immortal
Shared: Sandbox · Exploration · Simulation

Dragon's Dogma 2
Shared: Action RPG · Character Customization · RPG

No Rest for the Wicked
Shared: Action RPG · Exploration · Character Customization

Kerbal Space Program
Shared: Physics · Sandbox · Simulation

Session: Skate Sim
Shared: Exploration · Physics · Simulation

Disney Dreamlight Valley
Shared: Exploration · Character Customization · Sandbox

Starfield
Shared: Exploration · Character Customization · RPG

Amazing Frog?
Shared: Physics · Exploration · Sandbox