TripleA - TripleA is a free (under GPL) turn based strategy game based on Axis & Allies board game.
DayZ - DayZ is an open world multiplayer survival game that tosses you in the midst of a zombie apocalypse.
Puzzle Strike - Puzzle Strike is a Puzzle, Board, Single and Multiplayer video game created and published by Sirlin Games.
7 Days to Die - 7 Days to Die is a post-apocalyptic survival game, during which players must craft shelters and horde resources in order to survive waves of undead enemies. Read more about 7 Days to Die.
Lux Delux - Lux Delux is a game of strategy and domination inspired by the board game Risk.
Project Zomboid - The Ultimate Zombie Survival RPG.