Star Trek Online - Star Trek Online (STO) is a free to play MMORPG that takes place inside the Star Trek world.
Endless Space - Endless Space is an Amazing, Strategy, Science-fiction, Turn-based, Space, Futuristic, Exploration, Co-op, Single and Multiplayer Space Simulation created and published by Amplitude Studios.
X3: Terran Conflict - X3: Terran Conflict is part of the X number of video games.
Homeworld - Homeworld is an Action-Adventure, Science-fiction, Real-time Strategy, Real-time-tactical, Single and Multiplayer Space Simulation created by Relic Entertainment and published by Sierra Entertainment.
EVE Online - Player-created empires, player-driven markets, and endless ways to embark on your personal sci-fi adventure.
Stellaris - Stellaris is an Adventure-based, RTS (Real-time Strategy) Space, Sandbox, Sci-Fi, Single and Multiplayer video game created and published by Paradox Interactive.