Low Level Hell is a set of free wargames rules for helicopter actions in Vietnam.
Miniatures Rules
Generic Legions – Big Battle Version
Generic Legions is a set of free wargames rules for science fiction warfare. This versions is, as the headline suggests, for big battles.
Frontline Skirmish Game For MegaBlox
“a versatile, yet simple turn-based strategy game that is fully customizable. The game is designed to make use of Mega Bloks Halo sets, but you can use any kind of equally-sized figurines including cheap army men, and is meant to be played on any kind of table or flat surface. Similar to games like WarHammer 40k or even chess, Frontline Skirmish contains very loose, simple rules and maximum customization.”
The game is on the pay-what-you-want model.
Rabbidgerbal Wrestling!
Rabbidgerbal Wrestling! is a set of free rules for professional wrestlers in a ring.
Martial Arts Card Engine
The Martial Arts Card Engine is a set of free wargames rules for simulating fighting games and anime battles. From the game description:
MACE is a game for 2 – 4 players. MACE simulates the fantastic martial arts battles common to fighting games and anime. Each player is represented by a Fighter, a master of the martial arts complete with vicious Strikes and powerful Blasts of energy. The goal is to Knock Out all other players Fighters, with the last one standing the winner.
MACE uses a deck of playing cards, a hex sheet and some tokens, so is easy to play and requires no book keeping. MACE also features a unique order mechanic called Momentum, which allows you to choose when you act.