Steve’s Horse and Musket Rules are designed to be a simple set of rules emphasizing the three arms (horse, foot, guns) and command.
Rules: 20th Century
Red Actions! Interventionists
The Perfect Captain’s games are amazing combinations of form and function, with artwork that really matters to the game. They now have an expansion to their earlier Red Actions! Russian Civil War game that deals with the various nationalities that intervened in the strife. There’s also a new campaign.
Morschauser Inspired Russian Civil War Rules
The Battle Game of the Month Blog has the outline of a set of free wargames rules for playing games set in the Russian Civil War. They’re inspired by Joseph Morschauser’s rules.
Edwardian Splendor Wargames Rules
Edwardian Splendor is a set of free wargames rules for playing 54mm figures in the period 1880 – 1910.
Back of Beyond Campaign Rules
Tim’s Miniature Wargaming Blog has published some rules for his Back of Beyond campaign.