Which city kingdom of Ancient Greece implemented communism?

Yes, communism (or it's basic ideals of 'everyone' (read homoi) is equal) was rife in Sparta, I think, this is without checking, that it was King Agis I and perhaps a few others who when they noticed the gap between rich and poor getting larger, flattened out that difference forcably. Not to say there was physical resistance, but that he took everyone's property including his own and equally divided it up amongst the Spartan elites. Of course remember, the actual Spartans were more equal than the helots, who were little more than work animals