Well, (like the main poster) I can't give you sources - Wikipedia would probably do - but most if them have at least claimed to be Marxist!

The Russian-Revolution and the States that followed from it later (Mongolia, the states of Eastern Europe - East Germany, Hungary, Czechoslovakia, Poland, Bulgaria, Romania but not Yugoslavia) claimed to be Marxist-Leninist by which they meant they descended from the Bolshevik party and Lenin's interpretation of Marxism.

The Chinese Revolution initially claimed to follow the same line but later split and declared itself Marxist-Leninist-Maoist, I.e. Marxist-Leninism interpreted by Mao.

Various Asian communist parties went one way or another, which is how you end up with Vietnam and China fighting at the end of the 70s. Yugoslavia was always a different case as it liberated itself at the end of WW2, don't know what it officially claimed to be.

As for the totalitarianism that (or at least the totalising form of it) comes in with Stalin. North Korea today is a Stalinist state the way Stalin's Soviet Union was - secret police, cult of personality, massive gulag, disregard for life, and arguably more focused on economism than anything we would understand as politics.

So to answer your answer your question, or at least answer it in the terms of the rulers of the countries concerned, to would have to decide whether Stalin and Mao were a. Marxists - I.e. they believed they were; or b. they were flat out liars only interested in power; or c. they believed such simple-minded questions were the products of distorted bourgeois upbringing - I.e. it was perfectly possible to run a totalitarian communist state. I'm with c., but if course this is extremely contested....

There have been no such countries. Communism is utopical, it can't be achieved in reality, so most countries ruled by communists practiced either socialism or a different ideology, such as Juche in North Korea. Alternatively they turned back to capitalism, such as China under Deng Xiaoping.