Ross Macfarlane offers Hearts of Tin, a set of simple Horse and Musket rules:
Volley Fire is a set of 2mm wargames rules,
designed for lots of volley firing infantry with rifles, horse and cannon. It is meant for simplicity, so ignores morale and commanders and such likes, but maintains a certain amount of realism in certain areas. These can be written in at a later time. I’m very open for suggestions. Anyhow, on with the tour!
Each player has an army consisting of several companies of infantry or cavalry, and batteries of artillery. Infantry companies are made up of one to five platoons, cavalry of a similar number of squadrons, each of which is represented by one strip of models. Artillery batteries consist of a similar number of guns. Units can be either Close order (c.o.) or skirmishers.
The Square Brigadier is a set of horse-and-musket rules based on Bob Cordery’s Chess board game inspired by Joe Morschauser.
Here’s a Horse and Musket DBA Variant — primarily for Napoleonic and Seven Years War, but since the basic principles of war in that era covered a huge number of conflicts, you could adjust as needed.
Toy Soldiers is a set of free wargames rules for the Horse and Musket period. The author writes:
Abstracted rules for battalion combats in Horse and Musket period. A unit is a battalion. A single player might have 2-5 units under his command but only one commander. The intent of the rules is to allow players to bring a small command to the table of generic troops with no points system or national characteristics. The balance that I am aiming for is that a cavalry unit = an infantry unit = an artillery battery.
Infantry battalions are represented by 6 stands of several miniatures. In 15mm, 4 wide seems to work. Artillery batteries are represented by 3 stands. Limbers should also be included.
Units and commanders will always have at least a single D6 placed behind them. For units, this represents their disorder value (1 is well ordered, 6 being disordered). Commanders will have a Chaos dice which will always be at least 1 (well coordinated command) and may go as high as 6 (Ineffective command control). Often, units will also be marked by a single red die marking their stress. Stress goes from 0 to 6.