Graham Cookson offers a set of free wargames rules for the Jacobite Rebellion. He has helpfully also included painting guides, army lists and flags for printing.
Afterglow Skirmish Warfare In The Far Future
Afterglow Skirmish Warfare In The Far Future is a set of free wargames rules for 28mm figures and is designed to be used with a variety of manufacturers.
Constantinople Solo Board Game
Constantinople is a print-and-play board game tracking the thousand year history of the Byzantine Empire. From the BGG description:
A Victory Point Games States of Siege Series style solitaire wargame covering the millennium-long history of the Byzantine empire, from the foundation of Constantinople in AD330 until its fall in AD1453. The player uses military might as well as diplomacy and outright bribery to keep the many opposing forces at bay for as long as possible. Can you outlive the historic Byzantine empire, or will your efforts be relegated to an obscure footnote in the history books?
Naval Action
Naval Action, by Lou Coatney, is a set of free wargames rules for miniatures battles in the World War II Pacific Theatre. The page also provides some markers to use in place of model ships.
Atomic Highway Post Apocalyptic Role Playing
Atomic Highway is a set of free rules for post apocalyptic role playing.