D3 French and Indian War is a set of free wargames rules designed for play on a 6 inch square grid.
Scum of the High Seas is Rudi Geudens set of hex-based. card driven rules for playing games of Pirates on the high seas. Like others in this series, they’re based loosely on Richard Borg’s Battle Cry system.
Fire and Discipline was originally published (in 1988) to cover tactical warfare from 1740-1850. It is now in two versions, one focusing on firepower, the other on discipline. Both versions use the same basing and organization structure. The rules are lengthy because many simple questions are answered with the clarification examples. Optional rules are included to allow for more realistic and slower play for those who prefer it. After learning the rules most players will be able to play a friendly game by using only the pullout charts.
Here’s a variant of Warhammer Ancient Battles for the American Revolution. No. Really. It could work.
Phil Johnson and Les Benoot offer a pdf download of fog of war rules for the horse and musket era. These are a generic add on for other horse and musket rules sets, and are intended to reflect the problems offered by visibility and scouting on command control.