Cold War Naval Battles is a free print-and-play version of the classic Modern Naval Battles card game. We played the heck out of MNB back in the day.
Tactical Game X is a modern take on the classic Panzer Leader / Panzer Blitz games, which now are pushing fifty years old. They’re still great, though, and if you love them, you might want to take a look at Tactical Game X.
Cheapass Games offers Renfield, a card game about parts, tools, gravestones and “yummy delicious bugs.”
Unbound: Endless War is a free print and play game for two p layers in which you build a map and attempt to take over a players’ bases. It’s a pay-what-you-like game.