Champs de Bataille is a set of free wargames rules for ancients based on DBM. Each unit represents 125 to 250 cavalry or foot; more if a warband. The game is designed to be played on a hex board.
Link (direct download)
Rules: Ancients
Battle of Granicus
The Junior General offers a set of fast play rules as well as paper figures for the Battle of Granicus, in which Alexander The Great took on the Persian Empire.
Advanced Virtus Ancients Rules
Advanced Virtus is a set of free wargames rules for ancient warfare. They’re described as “fast and furious.”
Ancient Combat
Ancient Combat is a set of free wargames rules by Matt Cappetta.
Legio VI Macedonia
Legio Wargames offers Legio VI Macedonia, a set of free wargames rules for playing games set in the Helenistic through the Republican Roman eras. They’e designed for 6mm figures, with one 20mm x 20mm stand equaling 300 – 500 heavy infantry.