The Jackson Gamers have this set of free wargamesrules for the English Civil War. They use a card activation system, (not surprising, considering the acknowledged Brom influence), and d6s to resolve actions. These rules are 20 years old and in their 6th edition, so they are well-tested.
Larry Brom
Reasonable Brom
Reasonable Brom is a variant of Larry Brom’s standard rules for the 19th Century.
The Sword In Tibet TSATF Variant
The Sword In Tibet is a variant of Larry Brom’s venerable The Sword and the Flame rules. It focuses on actions in Tibet in the early 20th Century.
The Sword, The Flame, Machine Guns and Grenades
The Sword, The Flame, Machine Guns and Grenades is a World War II adaptation of Larry Brom’s The Sword and the Flame rule set.