TripleA - TripleA is a free (under GPL) turn based strategy game based on Axis & Allies board game.

The Battle for Wesnoth - The Battle for Wesnoth is a turn-based tactical strategy game with a high fantasy theme.

Domination - Domination is a game that is a bit like the well known board game of Risk.

Advanced Strategic Command - Advanced Strategic Command is a free, turn based strategy game.

Ticket to Ride - Ticket to Ride is a Turn-based Strategy, Puzzle, Board, Co-op, Single, and Multiplayer video game created and published by Days of Wonder and Asmodee Digital.

Tanks of Freedom - Classic turn-based strategy game with two armies fighting against each other.