There was this old school PC game I played one time at a friends house, can't remember the name of it. But it was more or less an open world in the galaxy, nonlinear.
Basically you got a ship, and you can fight with or trade with other aliens, and go to other planets, and even put bots on planets and farm them. One of the things I remember is you could trade chocolate bars to this one alien orbiting around Earth for some really powerful missiles. Also I remember dropping an archeology bot on this one planet and found some ancient artifacts or something like that.
This game is old, I'm thinking early 90s? Anyway it was a cool game, definitely ahead of its time.