Ram or Die is a set of free wargames rules (and paper figures!) for refighting the Battle of Salamis.
Miniatures Rules
God’s Acre Medieval Rules
God’s Acre is a set of free wargames rules for medieval battles. The rules were originally published in 1977 by Heritage Models.
La Drang Vietnam Rules
Junior General offers a set of free wargames rules for refighting the Vietnam War Battle of la Drang.
Seas of Lead WWII Naval Rules
Seas of Lead is a set of free wargames rules for World War II Naval games. Along with the rules are some good looking unit data cards that they made using the Magic Set Editor.
Red Hordes Russian Civil War Rules
Red Hordes is a set of free wargames rules for the Russian Vivil War. They’re similar to DBA/DBM.