FreeCiv - Freeciv is an open-source, turn-based strategy game based on Civilization II.
The Battle for Wesnoth - The Battle for Wesnoth is a turn-based tactical strategy game with a high fantasy theme.
Freeciv for Android - Port of Freeciv to Android - similar to Civilization series.
Advanced Strategic Command - Advanced Strategic Command is a free, turn based strategy game.
Widelands - Widelands is a free, open source real-time strategy game with singleplayer campaigns and a...
Tanks of Freedom - Classic turn-based strategy game with two armies fighting against each other.