Games like Heliopedia
Games like Heliopedia include SPORE™, Kerbal Space Program, Universe Sandbox, Spaceflight Simulator, and Avorion. We matched them by the tags players give Heliopedia on Steam (Simulation, God Game, Sandbox, Creature Collector, and Space Sim): closest matches first, and among equally close ones the better-known games.

SPORE™
Shared: God Game · Sandbox · Simulation

Kerbal Space Program
Shared: Simulation · Sandbox · Space Sim

Universe Sandbox
Shared: Simulation · Sandbox · Space Sim

Spaceflight Simulator
Shared: Sandbox · Simulation · Space Sim

Avorion
Shared: Sandbox · Space Sim · Exploration

Kerbal Space Program 2
Shared: Sandbox · Simulation · Exploration

X4: Foundations
Shared: Simulation · Space Sim · Sandbox

Space Engineers
Shared: Sandbox · Simulation · Space

Empyrion - Galactic Survival
Shared: Simulation · Space · Sandbox

Slime Rancher
Shared: Exploration · Simulation · Sandbox

Elite Dangerous
Shared: Space Sim · Simulation · Exploration

Planet Coaster 2
Shared: Simulation · Sandbox · God Game

Totally Accurate Battle Simulator
Shared: Simulation · Sandbox · Colorful

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

EVE Online
Shared: Space Sim · Simulation · Exploration

Ultimate Epic Battle Simulator 2
Shared: Simulation · Sandbox · God Game

SpaceEngine
Shared: Sandbox · Space Sim · Space

Planet Coaster
Shared: Simulation · Sandbox · Building

Little Kitty, Big City
Shared: Sandbox · Exploration · Simulation

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

Universe Sandbox
Shared: Simulation · Sandbox · Space

Slime Rancher 2
Shared: Simulation · Creature Collector · Cute

SPORE™ Galactic Adventures
Shared: Simulation · Sandbox · Exploration

The Universim
Shared: God Game · Sandbox · Simulation