18Africa is a free print-and-play board game from the 18xx rail game genre.
Retro Tactical is a set of free rules for use with the components of Squad Leader, Advanced Squad leader and other, similar board games.
Gunfighter is a pay what you want print-and play card game. From the author's description:
GUNFIGHTER is a Wild West themed dueling game where each player equips seven skills (cards) that remain for the entirety of the duel. These skills are mainly used to shoot, dodge, and aim - but also have various unique effects.
During the duel, both players take their actions at the same time. The goal is threefold: increase your two main stats (accuracy and bullets), successfully land shots on the enemy, and avoid the enemy's shots.
While the goals are straightforward, the many combinations of individual playstyles and possible skillsets create opportunities for players to try and "read" their opponents and play mindgames with each other.
Bronze Age Collapse is a three player DIY card game about the rapid decline of civilizations during the period 1200 - 1150 BC.