The Rules with No Name, the classic western wargames rules are available as a free pdf at The War Store.
Rules: 19th Century
Charge of the Light Brigade Rules
Charge of the Light Brigade is a set of free wargames rules in which each of five players controls a regiment of the Light Brigade in their fated charge.
Morschauser Meets MacDuff Rules
Morschauser Meeds MacDuff is Ross Mcfarlaine’s attempt to merge Joseph Morschauser’s 1962 rules with other influences to create a fast play horse and musket set of rules.
Featherstonian Rules For The Franco Prussian War
Tony’s Toy Soldiers’ blog offers a two-page set of Featherstonian Rules For The Franco Prussian War.
The Four Eyed Dog Is Dead Taiping Rebellion Rules
The Four Eyed Dog is Dead is a set of free wargames rules for games set in the Taiping Rebellion.
For what it’s worth, the Taiping Rebellion is one of the least known — and at the same time, deadliest — conflict in world history. Taking place in China from 1950 to 1864, best estimates say that the Taiping Rebellion resulted in between twenty and forty million dead.