Most of the independent human systems doing just fine without the Imperium tyvm
Eldar
Some Necrons, maaaaybe. It’s hard to tell with them sometimes.
Hrud mostly seem to just want to be left alone.
A lot of aliens just chilling
Fun Fact: the Imperium doesn’t actually span most of the galaxy. Nor do they really “control” the area around their systems.
Because of how FTL works in 40k, some areas just aren’t accessible to them. There’s a full on insectoid empire called the Q’orl near Terra that they didn’t have access to or know about until the Warp currents shifted.
And apparently their technology is even enough to be a potential threat… And the Imperium learned this when they immediately tried to kill them, obviously