Country is a little vague so I'll supliment state in it's place. I'd argue there are communist societies but no communist states. "communist states" may be an oxymoron.

A useful way to think about self described communist states is that they are attempting to build communism. Whether or not their strategies are effective is up for rigorous debate of course.

Communist societies on the other hand have existed since the dawn of humanity. I read an interesting book titled The Dawn of Everything by David Graeber and David Wengrow. They cover a variety of indigenous groups' economies and social structures. Some could be described as communism, others were as exploitative or worse than our current society. The San tribes are a modern example of an egalitarian society or maybe more accurately a group of egalitarian societies. I'm also interested in the Zapatistas and what the folks in Northern Syria are doing but I doubt they constitue communism.

Anyway I'm no authority on these things but I hope you found the perspective interesting. The audiobook for the Dawn of Everything is fastinating and a local library might have a copy if you want to check it out.