Empress Miniatures offers a set of free wargames rules called Damned Wobbly Gentlemen, designed for recreating battles of the Zulu War.
rules
Final Round WWII Rules
Final Round is a set of free wargames rules for World War II infantry combat games.
Rabbidgerbal’s Super Simple 1PG Sci-fi Skermish Rules
Rabbidgerbal’s Super Simple 1PG Sci-fi Skermish Rules is a set of free wargames rules meant as a 40K replacement.
Yes, that’s really how the author spelled “Skirmish”
Cold Steel Miniatures Rules for 1690 to 1850
Cold Steel is a set of free wargames rules for the period 1690 to 1950 offered by Historic Enterprises. The first release offers the basic rules, plus specific addendums for the Wars of Napoleon and the War of 1812. The nice thing about the rules is that they offer a flexible scale system, with each figure representing between 5 and 60 men. This should allow you to fight a wide variety of battles with the same rules set.
14 – 18: Vistula, Verdun, Versailles
14 – 18: Vistula, Verdun, Versailles is a set of free wargames rules for playing the first World War in 2mm scale.