Turn-based 4X (explore, expand, exploit, and exterminate) strategy game series where players build a thriving civilization through ages of advancements.
The Battle for Wesnoth is a turn-based tactical strategy game with a high fantasy theme.
Freeciv is an open-source, turn-based strategy game based on Civilization II. Inspired by the history of human civilization, the game commences in prehistory and your mission is to lead your tribe from the stone age to the space age...
Statebuilder is a 4X strategy game in a historical setting where players direct an empire from the early dawn of civilization to modern times. The browser-based game is built to be fast but attractive and highly playable with an advanced AI that plays just like real players...
OpenFracas is a free, open-source game that is similar in style, but not in specifics, to Risk. On randomly generated and customizable maps, humans are pitted against other humans and AIs in an attempt to eliminate all other players or teams.
Subterfuge plays out in real-time over the course of a week or more. Players check in a few times each day to assess their situation, issue or modify orders, and engage their fellow players in diplomacy and subterfuge.