Hedgewars - Hedgewars is a Free to play, Single-player and Turn-based Strategy video game developed by Hedgewars Development Team.
TripleA - TripleA is a free (under GPL) turn based strategy game based on Axis & Allies board game.
Worms - Worms is a Superb, Turn-based, Strategy, Online, Single and Multiplayer video game developed and published by Team17 Software Ltd.
Warlight - Warzone is a customizable Risk-like strategy game where you compete with your friends to conquer the world.
Pocket Tanks - Pocket Tanks is the fast-paced artillery game that is simple to learn, and fun to master.
Domination - Domination is a game that is a bit like the well known board game of Risk.