De Bellis Horribilis is a set of free wargames rules for The Great War based on DBA.
Miniatures Rules
Furious Reason Rules 18th Century Rules
Furious Reason is a set of free wargames rules that combines Fire and Fury with Age of Reason.
JUGS: A Game of Big Stompy Robots
JUGS is a set of free wargames rules for science fiction combat with giant robots.
Giant robots. How can you go wrong?
Dragon Fight Aerial Combat Rules
Dragon Fight is a set of free wargames rules for aerial dragon combat.
Fokker Fodder
Fokker Fodder is a set of free wargames rules for World War One aircraft battles. The rules are designed for both single battles, and for campaigns.