Star Trek: Supremacy is the successor of the original Star Trek: Birth of The Federation. The game can be played with up to 6 major races (Earth Federation, Kardasiani, Klingon, Ferengi and even Dominion) in a large star map.
FreeOrion e new free version of the well known game Master of Orion. The game is galactic strategy. Conquer new planets, and keep yours from being taken. Develop technologies. Build ships and fight. There is one goal - to conquer the galaxy.
Colonization called in the new free version - FreeCol is a similar to Civilization turn-based strategies game. The objective is to build an independent nation. You begin the settlement of America with a handful of colonists. Starting from scratch, you must build the "new world."
Maybe the most popular turn-based game for all the times - Civilization now has a new and free variation called FreeCiv. In the game you have to develop your own empire, starting from the stone age and reaching to the space age. Your mission is to build a great civilization, to fight competitors and to develop your nation at all means.
In this real time strategy, you are the X-COM - a team created to fight the alien invaders. You keep fighting and meanwhile research everything you found during your battles. Finding new types of weapons, and valuable intelligence, your goal is to defeat the aliens.
X-Force is a game inspired by the classic series UFO: Enemy Unknown, XCOM: Terror from the Deep и XCOM: Apocalypse, where player defend the Earth from alien invaders.