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.
Sins Of A Solar Empire - Sins of a Solar Empire is an Adventure, Strategy, Real-time-strategy, Science-fiction, Exploration, Aliens, Single and Multiplayer Space Simulation developed by Ironclad Games and published by Stardock.
Elite Dangerous - Elite Dangerous is a 2015 Trading, Action, Sci-fi, Exploration, Open World and Space Simulation by Frontier Developments.
Planet Capture - Browser-based, sci-fi space RTS game.
Star Conflict - Star Conflict is a free MMO action game and space simulator that was introduced in 2012.