Boonta Eve Classic is a set of free wargmes rules for pod racing in the Star Wars Universe. The rules are designed for use with those old Galoob Micromachines, which can still be had for a reasonable price on Ebay:
rules
American War of Independence Wargames Rules
American War of Independence is a set of free wargames rules based on Neil Thomas’ Napoleonic Wargaming and Ancient and Medieval Wargaming. Interestingly, all movement is based on “base widths.”
Away Team Astro Miniatures Skirmish Game
Away Team is a set of free wargames rules for a Star Trek-style landing party expeditions.
There’s also a set of 15mm not-Star Trek miniatures.
Tough Men With Iron Balls: Piquet For Age of Sail
Tough Men With Iron Balls is a set of free wargames rules for fighting 7 Years War and Napoleonic Naval Battles.