Games like X: Beyond the Frontier
Games like X: Beyond the Frontier include X4: Foundations, Elite Dangerous, X Rebirth, X3: Terran Conflict, and Stellaris. We matched them by the tags players give X: Beyond the Frontier on Steam (Simulation, Space, Strategy, Sci-fi, and Singleplayer): closest matches first, and among equally close ones the better-known games.

X4: Foundations
Shared: Simulation · Space · Space Sim

Elite Dangerous
Shared: Space · Simulation · Space Sim

X Rebirth
Shared: Simulation · Space · Sci-fi

X3: Terran Conflict
Shared: Simulation · Space · Sci-fi

Stellaris
Shared: Space · Strategy · Sci-fi

Kerbal Space Program
Shared: Simulation · Space · Space Sim

EVE Online
Shared: Space Sim · Space · Simulation

No Man's Sky
Shared: Space · Sci-fi · Open World

SPORE™ Galactic Adventures
Shared: Simulation · Space · Strategy

Endless Sky
Shared: Space · Simulation · Sci-fi

Hardspace: Shipbreaker
Shared: Space · Simulation · Sci-fi

Rebel Galaxy
Shared: Space · Sci-fi · Singleplayer

Dyson Sphere Program
Shared: Space · Simulation · Sci-fi

X3: Reunion
Shared: Simulation · Space · Strategy

Starpoint Gemini Warlords
Shared: Space · Simulation · Strategy

Starfield
Shared: Space · Singleplayer · Sci-fi

SPORE™
Shared: Simulation · Space · Sandbox

Starminer
Shared: Space · Space Sim · Sci-fi

Avorion
Shared: Space · Space Sim · Sandbox

Jurassic World Evolution
Shared: Simulation · Strategy · Singleplayer

X2: The Threat
Shared: Space · Simulation · Strategy

FTL: Faster Than Light
Shared: Space · Strategy · Sci-fi

Empyrion - Galactic Survival
Shared: Simulation · Space · Space Sim

Space Engineers
Shared: Space · Simulation · Sandbox