Games like FreeSurf
Games like FreeSurf include Goat Simulator 3, Amazing Frog?, skate., Session: Skate Sim, and Shredders. We matched them by the tags players give FreeSurf on Steam (Exploration, Sports, Sandbox, Nature, and Physics): closest matches first, and among equally close ones the better-known games.

Goat Simulator 3
Shared: Exploration · Sandbox · Physics

Amazing Frog?
Shared: Sandbox · Exploration · Physics

skate.
Shared: Sports · Sandbox · Character Customization

Session: Skate Sim
Shared: Sports · Exploration · Physics

Shredders
Shared: Sports · Physics · Nature

Ultimate Fishing Simulator
Shared: Sports · Nature · Exploration

BeamNG.drive
Shared: Physics · Sandbox · Simulation

Steep™
Shared: Sports · Exploration · Open World

Goat Simulator
Shared: Sandbox · Physics · Simulation

PEAK
Shared: Exploration · Physics · 3D

theHunter: Call of the Wild™
Shared: Nature · Sandbox · Open World

Rooftops & Alleys: The Parkour Game
Shared: Sports · Exploration · Simulation

CarX Drift Racing Online
Shared: Sandbox · Physics · Simulation

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

Black Desert
Shared: Exploration · Sandbox · Action-Adventure

SnowRunner
Shared: Exploration · Sandbox · Simulation

Totally Accurate Battle Simulator
Shared: Sandbox · Physics · Simulation

Garry's Mod
Shared: Sandbox · Physics · Simulation

Kerbal Space Program
Shared: Sandbox · Physics · Exploration

Sledding Game
Shared: Sandbox · Physics · Relaxing

Kerbal Space Program 2
Shared: Exploration · Sandbox · Physics

Space Engineers
Shared: Sandbox · Physics · Simulation

Jalopy
Shared: Exploration · Nature · Relaxing

Super Battle Golf
Shared: Sports · Physics · Exploration