The USSR was not even the first socialist society. I suggest reading up on the Paris Commune. Other than that, the Diggers are an earlier community that practiced a sort of socialism.

However, socialism and communism require industrialization to work, so you'd not find any actual such societies before the industrialization. However, Marx said that early hunter-gatherers practiced a form of proto-communism, and modern studies have shown that those communities were somewhat egalitarian.