What is there?

Not in reality, but in the view of the US government. What exists “legally?” There is of course the US government. There are individual human beings, as defined by the US government. There are corporations, profit and non-profit, chartered by the US government or another government. There are other sovereign states, like Belgium and China, and maybe the fifty US states. Maybe there are NGOs distinct from non-profit corporations. Maybe groups (nations?) of native Americans are something different. What about organized criminal gangs? Are there some few categories in which US law places every human or group of humans?