Simplus Medieval Miniaturis Rules (SMR) is set of free wargames rules for battles in the medieval era.
Rules: Medieval
To Cry A Joust
To Cry A Joust is a set of free wargames rules for jousting combats.
Are You Being Serfed? Wars of the Roses Rules
Are You Being Serfed? is a set of free wargames rule for the Wars of the Roses. The author notes:
I believe they will give a fast and fun game. We are going to have in the region of 40+ units, 800+ figures on the table and with possibly only 2 players they need to be.
Swordplay Man To Man Skirmish Rules
Two Hour Wargames offers Swordplay, a one-to-one skirmish game with sword, shield and bow.
Chivalry — Old School Games Workshop Magazine Game
Realms of Chaos Blog has a posting about the old GW game called Chivalry, which appeared in an issue of White Dwarf. All the relevant pages there are posted, so you can recreate this classic on your own. It’s a card system for combat between knights.