I accidentally found Rodent's Revenge today, and it got me looking for other old games I used to play (1990s-era).
The one I can't think of the name to was a space strategy game. You went around getting resources from planets and trying to take over enemy planets. The player controlled one space ship, that could be upgraded. If it was destroyed, you started back with the basic ship.
I remember you could "Plague" planets to convert them to uninhabited, and then put your people on them to capture them.
You could also fund their various politics to convert them to your alignment - which cost you money.
You could "suck up" people from friendly planets and deposit them on uninhabited planets to colonize them.
I've been running in circles on Google and other search engines.
It was kind of the great-great-great-grandfather to Star Wars Empire at War. Even down to the green-yellow-red IFF. Thanks!