Osprey has gone into miniatures rules in a big way (and it makes me wonder why they didn’t do so long ago). On this page, you can get copies of the play sheets and reference sheets for In Her Majesty’s Name, Dux Bellorum, A World Aflame, Gods and Mortals, Ronin, On The Seven Seas, A Fistful of Kung Fu and Lion Rampant.
Into the Darkness is a set of simple free wargames rules for skirmishes.
The author writes:
Into The Darknessis a tabletop war-gamefor two players. It is played on a 4×4 board, with each player alternating taking turns. Each player controls one (1) team, which may comprise as few as three but as many as nine models. Each model is given three points with which to purchase gear, though points may be gained with experience.
Plastic Hell is a set of free wargames rules for playing games with bags of dollar store plastic figures.
Three Inch Glory is a set of free wargames rules for battles with Playmobil figures. The games are set in the 18th Century.
Here are a set of rules for playing Calvinball, from the legendary comic strip Calvin and Hobbes. The rules come with figure cut-outs.