The Cathars (the pure ones) were a sect of pre-Reformation Christians of Southern France who broke with the Papacy and were (mostly) exterminated during the Albingense Crusade…
It’s worthy to note that they were pescatarians (vegetarians except for fish because of the Jesus multiplying stories in the Bible) and maybe could have moved Europe out of the Middle Ages (at least into reformation) 300 years earlier had they not been squashed.
While I prefer cities/neighborhoods where people of different lifestyles live side by side minding their own business, and I certainly don’t want to mix seasteading with religion, it is impossible to miss that many religious communities would love the freedom from interference it offers.
In North, South, and Central America as well as Siberia there are Mennonite colonies (or Raskolniki, “Old Believers” in Russia) thriving in places where other attempts at settlement are fledgling at best. These are community oriented people who renounce violence, more than abide by the principle non initiation of force, and unlike the amish, do not shun technology altogether.
In places like Western Paraguay or Belize your best bet at getting anything at all or a prefabricated wooden cabin respectively is the Mennonites.
The “natural limit” for human communities was discovered studying how Menno colonies split when they reach 80 or so inhabitants.