One Man One Gun is a set of free wargames rules for plastic army men.
rules
OMOG Musket Rules
OMOG Muskets is a set of free wargames rules for small unit actions in the horse and musket era, 1700 – 1849.
Bladestorm Quick Start Rules
Bladestorm, the classic fantasy wargames rules from Iron Crown Enterprises in the 1990s is back in a second edition. You can get the quickstart rules at the link.
Wild West Exodus Free Core Game Rules
Wild West Exodus is a skirmish game that mashes the 19th century American West with steampunk and horror themes. You can get the free starter rules here.
Blaze Away WWII Rules
Blaze Away is a set of free wargames rules for company and battalion level actions in World War II. It’s designed for 10mm – 20mm figures.