Military Memoirs is a parlour game from the mind of Jim Wallman. In it, the players tell outlandish tales of their military adventures.
I grew up reading The General, Avalon Hill’s monthly magazine featuring its games. You can find an archive of all of the original issues of The General at the link.
Table Air Combat is a pay-what-you-want, print-and-play game of WWII air combat. All you need are the prints and some six sided dice.
Paraguay is a free print-and-play wargame about the 1864 war involving Brazil, Uruguay, Paraguay and Argentina. It’s designed for 2 – 4 players.
Clash On The Fringe is a set of pay-what-you-want rules for military space adventure. They’re designed for use with whatever figures you have.