Quick War is a set of free wargames rules for WWII games using 1:144 miniatures. From the BGG author’s description:

This is a set of rules to play a WWII game with 1:144 miniatures. It doesn’t use a lot of look up tables, and is easy to learn. That’s why I call it “Quick War”. This set of rules uses no game board, instead units are moved by measurements in inches, and rulers are used also for firing weapons. I use different colors of felt to denote hills, forest, water, and roads. Units may be hidden and put on opportunity fire, or be activated to move and fire. There are rules for artillery and infantry as well. Infantry may be used as artillery spotters, or to attack other infantry or armor. There is also Infantry support which includes heavier weapons such as bazookas.