Trench Raider: WWI Waraming In Ten Minutes

Trench Raider is a set of free wargames rules for WWI trench warfare.

Jutland: The Rules of the Game

Jutland: The Rules of the Game are a set of free wargames rules for large scale WWI Fleet Actions.

Mimi and Toutou Go Forth WWI Naval Rules

Mimi and Toutou Go Forth is a set of simple naval rules for WWI naval battles on Lake Tanganyika. Obscure, to be sure, but intriguing.