Belarus aside, which ones? Because I can't think of any.
Seriously, it's been over thirty years since the end of Cold War and people still think there are some eastern European states associated with Russia... Almost all of them are in the EU now with the notable exception of Ukraine which is in a state of de facto war with Russia. Even Lukashenko has a bitter-sweet relationship with Putin.
Of these, Georgians are as anti-Kremlin as one could be, they were at open war against Russia in 2008. Armenia is a pro-European democracy. Azerbaijan, probably the least democratic of these, doesn't long for Kremlin either. In general, all eastern-European countries were happy to become independent from Russia and there is no reason for them to choose Russia over the EU.
So one would never refer to them as "Russia and associated eastern european states" because, frankly speaking, Kremlin has no friends in Eastern Europe. (I specifically differentiate between Kremlin with its cold-blooded war crimes, and Russian people, who are normal nice folks and are a significant part of the total population of Eastern Europe.)
I've seen some consider Kazakhstan to be a part of Europe. I suspect the region stretches, depending on the speaker, far enough east to encompass the speaker's country, regardless of its location (but no further).
Kazahstan is in Central Asia probably because it's so big. Even their timezones are prefixed with Asia. The Caspian Sea and the Ural Mountains are the eastern limits of Europe, so everything on the Caspian's west bank is in Europe. Astrakhan is in Europe for instance.
Seriously, it's been over thirty years since the end of Cold War and people still think there are some eastern European states associated with Russia... Almost all of them are in the EU now with the notable exception of Ukraine which is in a state of de facto war with Russia. Even Lukashenko has a bitter-sweet relationship with Putin.