Kings of the Ring is a set of free wargames rules for one-on-one combats.
skirmish
Front Rank Fire Zulu Skirmish Rules
Front Rank … Fire is a set of free wargames rules for the Zulu War of 1879. The game is for skirmish actions in 15mm to 25mm figures, and you’ll need a ratio of about 3-1 Zulus over Brits to make it a game.
Medieval Skirmish Rules
Lord Merlin has a set of free wargames rules for large (70mm or 1:20) scale figures. There are three levels to this skirmish rules set: “simple”, “better” and “more realistic.” There also are some cute pictures of a “knights of the dinner table” game.
Ruination Science Fantasy Game
Ruination is a set of free wargames rules for science fantasy skirmishes.
Such ruin, such destruction, such misery and woe has been visited upon this land. Empires have fallen, kings have deserted their thrones and faith has forsaken the Church. The champions of old have been defeated. Ancient alliances lie in ruins. Now new heroes are rising up, seeking a new path, forging their own destiny. Power is unguarded and is ready to be grasped by those daring enough to seize it.
Ruination is a game of duelling heroes – implacable warriors, cruel sorcerers, devious rogues and other lone champions intent on battling their way across this devastated landscape. Now is the time for action, now it is time to unleash your inner Hero, to find your path to greatness and the glory that awaits you!
DayZ Zombie Wargame/RPG Rules
Day Z is a set of campaign wargame and RPG skirmish rules for games set in a zombie apocalypse. The author writes:
This DayZ ruleset is played on a simple grid map, with each grid square representing an area fifty meters on each side. The majority of towns and rural areas can be represented by a twelve-by-twelve map, though some larger areas such as Chernogorsk, Elektrozavodsk, and Solnichniy are better-suited by a double-wide, twelve-by-twenty-four map. The game starts out on the coast of Chernarus, a former Soviet republic currently experiencing a virulent outbreak of a plague rumored to originate from an island offshore of Taviana. The plague does not appear curable, and causes symptoms in its victims similar to ‘zombies’ described in popular media. Its extents are currently unknown, but it is believed to have spread across much of Europe and the Middle East.