Alan Saunders offers Great Northern War, a set of free wargames rules that he describes as:
A heavily modified version of the Horse & Musket/Pike & Shot rules in Neil Thomas’s ‘One Hour Wargames’ specifically for use with the Great Northern War.
The Miniature Wargaming Editor
See The Elephant American Civil War Rules
See The Elephant is a set of free wargames rules for the American Civil War played on a chess-like grid.
Mighty Mean Fowt Fights ACW Rules
Mighty Mean Fowt Fights is a set of free wargames rules for American Civil War battle games played on a square grid.
Struggle Against Everything And Everybody
Alan Saunders offers Struggle Against Everything And Everybody, a set of free wargames rules for the Mexican Revolution of 1910 – 1920.
A Hotter Fire ACW Naval Rules
A Hotter Fire is a set of free wargames rules for naval combat between civil war ironclads.