Alan Tidders’ free wargames rules for the English Civil War are his own modifications of the Jackson Gamers’ rules set.
pike and shot
Tree of Battles 14th – 15th Century Wargames Rules
Tree of Battles is a set of free wargames rules for battles of the 14th to 15th Centuries.
Koku Samurai Warfare Rules
Koku is a set of basic Samurai warfare rules with a mechanism for purchasing your troops.
Richard Bradley’s Pike and Shot Skirmish Rules
Richard Bradley offers a set of Pike and Shot Skirmish rules.
Argad Medieval Skirmish Rules
Argad is a set of free wargames rules for skirmishes in the dark ages and for pirates in the 17th and 18th centuries.