Free War, along with it's preset countries, allows PMCs (Or Private Military Companies), Which act like small countries. There aren't very many, but they can attack anyone they want, meaning they can enter a war and help either side, and can build their own equipment, much like a country. Here's the current list of them (This list MAY be updated in the Future)

Vyrrolf Combat Solutions (VCS)

(Possible Updates coming soon.)