High Crusade are a set of free wargames rules for 15mm / 25mm science fiction games.
rules
Wrath of the Gods Fantasy Skirmish Game
Wrath of the Gods is a set of free wargames rules for skirmishes with a classical mythological flavor.
The Sword In The Philippines Rules
Larry Brom’s The Sword and the Flame may be as close as anyone has come to a “universal” wargames set. Here’s a variant of the game for the Moro Rebellion and the US Involvement in the Philippines: The Sword In the Philippines
Warhammer American War of Independence
Warhammer American War of Independence is a Warhammer AWI variant.
Battlefields: From Broadswords To Bullets
Battlefields: From Broadswords To Bullets is a set of free wargames rules for battles ranging from ancients to moderns. They’re designed for 20mm / HO Scale figures.