Fight Dice is a set of free wargames rules that uses a neat dice pool system, where the players allocate handsfull of six sided dice to their actions.
Caliburn’s Wrath is a set of free wargames rules from Matt Cappetta for the Arthurian period. The rulesCaliburn’s Wrath are “intended to represent intense clashes between small bands of foot soldiers.”
The Hot Lead and Steel Sinews Yahoo group focuses on pulp-era gaming. There are also a set of playtest rules for the period, called “Noir.” Unlike other adventure-miniatures games, this set of free wargames rules is specifically focuses on the period, featuring such things as “hero points” to capture the flavor of the pulp novels.
Jon Clarke has writtenUrban Myth , a set of free wargames rules set in a kind of a near future cyberpunk setting. What makes these rules stand out is in the basic die mechanism. It uses a d100 system (rolling two ten-sided dice), but you read the dice differently depending upon the difficulty level of the task:
All rolls are on d100 needing to get equal to or less than the Attribute being tested against.
How the dice are read depends on the difficulty of the test. If the action is easier it may be reduced one step or more, if harder increased one step or more.
There are three levels of difficulty for any task:
Easy: roll d100, read the dice the worst way in relation to the task (generally speaking you read the dice to fail, but if they succeed either way place the lowest dice as tens)
Normal: roll d100, identify one dice as tens & one as units before rolling.
Hard: roll d100, read the dice however you like.
Rex Hurley has written a set of free wargames rules for playing Last of the Mohicans with 25mm – 28mm wargames miniatures. The rules are relatively simple, and include statistics for all of the main characters, such as Hawkeye, Uncas, Chingachgook, Magua, et. al.
There’s also a page of pictures for inspiration.