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.
Rules: WWII
WWII Naval Rules
Here’s a set of very simple WWII Naval Rules.
Destroyer Commander
Destroyer Commander is a variant for Mongoose Games’ Victory At Sea that focuses on smaller ship actions. I have always wanted to do Destroyer and PT Boat games.
Crush The Fascist Vipers WWII Rules
Crush The Fascist Vipers is a set of free wargames rules for 6mm WWII games.
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.