This site has a couple of free rule sets. Battle reports using these rules are occasionally posted on my blog http://gridbasedwargaming.blogspot.com.au
Machine Age (WW1 - 1918) rules (version 2) - Updated for tanks, armoured cars and aircraft, among other additions. Based on One Hour Wargame by Neil Thomas. These fast-play rules are geared to the last year of WW1 on the Western Front. In particular, the German Spring Offensive (Kaiser's Battle) a series of attacks launched March 1918; and the following Allies Hundred Days Offensive against German lines from August to November 1918.
AWI One Hour Wargame Grid-Based - Updated for command ranges, 6" square gridded table, moral and different combat mechanics. Updated 3rd January 2016.
WW2 Grid-Based Rules - These house rules are a cocktail of One-Hour Wargames with a dash of PanzerBlitz added. Each unit represents a company and games are played on a gridded table. Version 9 Updated 14 September 2016.
WW2 North Africa Grid-Based Rules - These rules are a variation of Lock ’n’ Load’s free to download Tank on Tank living ruleset and have been adjusted for the WW2 Western Desert Campaign 1940-1943 between the AXIS forces and Allies. These adjustments include: D10 combat, smoke screens, minefields, movement of units and the resulting dust, and visibility at various times of the day.
D3 Horse and Musket Rules - This set of rules is a variation of One Hour Wargames Horse and Musket rules by Neil Thomas. The rules use D3 dice to determine hits and a 9 hit system, they use a simple activation system to create increasing friction as units take hits. Updated 18 September 2021.
See below for rules...