Tank Duel is a set of free wargames rules for WWII games where each player commands a single tank.
Hell On Wheels is a game of tank warfare in France in 1944. Players command a platoon of tanks.
Here’s a set of free wargames rules for operational level actions during WWII. Battalions are represented on a 2×2 base, and the entire thing is inspired, it seems, by Volley and Bayonet.
Krieg Ist Mist is a set of free wargames rule for 6mm games set in WWII.
Operational Art is a set of operational level WWII rules.