Games like Starpoint Gemini 3
Games like Starpoint Gemini 3 include Starfield, Elite Dangerous, No Man's Sky, Fallout 4, and Rebel Galaxy. We matched them by the tags players give Starpoint Gemini 3 on Steam (Space, Simulation, RPG, Space Sim, and Exploration): closest matches first, and among equally close ones the better-known games.

Starfield
Shared: Space · RPG · Exploration

Elite Dangerous
Shared: Space · Space Sim · Simulation

No Man's Sky
Shared: Space · Exploration · Open World

Fallout 4
Shared: RPG · Exploration · Open World

Rebel Galaxy
Shared: Space · RPG · Sci-fi

Starpoint Gemini 2
Shared: Space · Simulation · RPG

X4: Foundations
Shared: Space · Simulation · Space Sim

EVE Online
Shared: Space Sim · Exploration · Space

Cyberpunk 2077
Shared: RPG · Open World · Singleplayer

Fallout: New Vegas
Shared: RPG · Exploration · Open World

Kerbal Space Program
Shared: Space · Simulation · Space Sim

Endless Sky
Shared: Space · Simulation · Sci-fi

X Rebirth
Shared: Space · Simulation · Space Sim

Starcom: Unknown Space
Shared: Space · Exploration · Space Sim

SPORE™ Galactic Adventures
Shared: Simulation · Space · Action

Empyrion - Galactic Survival
Shared: Simulation · Space · Exploration

Spaceflight Simulator
Shared: Space · Simulation · Space Sim

Starpoint Gemini Warlords
Shared: Space · RPG · Simulation

The Long Dark
Shared: Exploration · Open World · Simulation

Between the Stars
Shared: Space · RPG · Simulation

STAR WARS Jedi: Survivor™
Shared: Action · Singleplayer · Space

PULSAR: Lost Colony
Shared: Space Sim · Simulation · Space

The Forest
Shared: Crafting · Open World · Action

Starcom: Nexus
Shared: Space · RPG · Exploration