[n4r9]

What about Rojava? Maybe not strict anarchism but not too far off. Definitely not a theocracy or rigidly traditional.

Paris commune, revolutionary Catalonia and Ukrainian free state also spring to mind, though all were bowled over by neighbouring forces.

[api]

Catalonia is one I'm familiar with as an example of something a bit like syndicalism working, but it isn't that big and it isn't entirely standing on its own.

These also, as you say, tended to get bowled over eventually.

Try to scale these systems to the whole world and I don't think it would work... not unless you're much closer to post-scarcity.

[n4r9]

One thing worth noting is that Anarres in The Dispossessed has a population of only around 20 million. It's not actually that much bigger than revolutionary Catalonia was - maybe 2-3 times the population?