Pioneer - Pioneer is a space adventure game set in the Milky Way galaxy at the turn of the 31st century.
X - It is a science fiction space trading and combat simulator series.
Kerbal Space Program - Build spacecraft, fly them, and try to help the Kerbals to fulfill their ultimate mission of conquering space.
EVE Online - Player-created empires, player-driven markets, and endless ways to embark on your personal sci-fi adventure.
Star Citizen - 1, 966, 341. Active citizen. Help us make Star Citizen a reality! Become a backer of the next-generation of Space-man. Reserve your ship.
Elite Dangerous - Elite Dangerous is a 2015 Trading, Action, Sci-fi, Exploration, Open World and Space Simulation by Frontier Developments.