I know there was Warsaw Pact but the member states were basically under the thumb of the Soviets. I know China and USSR had a rift resulting in Sino-Soviet Split but they were committed to aiding North Vietnam.
Was USSR the only country more proactive in spreading communism or did other countries attempt to foment revolutions as well?
You had Cuba trying to spread "the revolution" to places such as Angola. It's important to note that in quite a few places, at least at the start, the nations of the warsaw pact were made up of legitimate, dyed in the wall Communists who may have genuinely believed in their cause.
While there were times (such as the vicious crackdown on the Czechs) where the Soviets said they'd gone too far, it would be misleading to say they were entirely puppet states.
Over the course of the Cold War, the Communist world became larger and more fissile. The Warsaw Pact, as you know, was a military agreement on collective defense. There was also a parallel economic organization, the Council for Mutual Economic Assistance(COMECON) whose function was a kind of international central planning--member countries agreed among themselves how much wheat each would produce, how many cars, how much rice, etc. and the terms on which they would trade.
Warsaw Pact countries had joint military command (which was of course coordinated from Moscow).
Apparently, in 90s some of those countries (Poland, Czech Republic and Hungary) published plans of Soviet nuclear attack on Europe.