The Armchair General writes:
A GLORIOUS VICTORY (AGV) is a reasonably quick and easy set of wargames rules designed for the period of warfare from around the early 15th century through to the latter part of the 16th century, thus covering the War of the Roses and most of the Renaissance period.
Warflag has some modifications for the commercial Age of Reason rules to allow you tu use them to fight battles in the Age of Marlborough.
Charge Yr Pikes is a set of free English Civil War miniatures rules. They use a card driven turn mechanism.
Junior General has a new set of rules and a scenario for fighting the English Civil war Battle of Naseby.
A variant of the One-Hour Wargames rules, the D3 ECW rules use a combination of D3 (1,1,2,2,3,3) and D6 dice.