Fog’s Soldiers offers a set of free miniatures rules for Road Cycling, and not incidentally, a line of miniatures to go with it. You don’t need them, though, because you also can download printable rider tokens.
Rules: General
Brickhammer Lego Wargames Rules
Brickhammer is a set of free wargames rules for playing wargames using Lego and minifigs.
Minifigz Lego Combat Rules
Minifigz is a set of rules for combat with Lego figurines.
Plastic Brigade
Plastic Brigade is a set of fun rules for dollar store toy soldiers.
Mike Mike Projectile Wargaming
Mike Mike Projectile Wargaming is a set of free wargames rules for games of that sort where you use some short of shooter (such as a rubber band gun) to knock over the figures.
Use with plastic only.