The Grange/Order of Patrons of Husbandry; almost dead, but they have huge trusts and real estate, so it squeaks along. Their final drama, which may be viewed after years of membership and service in the preceding levels, is a procession style presentation of the Eleusinian. Otherwise dull, expensive and bureaucratic.
Then there's Feraferia. Very pagan, lots of dancing in fields and groves, probably a miniature stonehenge nearby.