No April Fools, but an honest request. One of those resources that other communions have that we do not have is a comprehensive list of every Unitarian, Universalist and Unitarian Universalist church that has been: the living and the dead. At the very least it would help establish a frame for a missiological history and might surface some "hidden histories" that challenge received narratives, say, around the success or failure of the midcentury Fellowship movement. (Which the Universalists also had, with a non-competative arrangement with the Unitarians, details to come. Or that gold mines, oil wells or a-bomb plants attract Unitarians.)
We can start with something easier? Say, all churches in existance in 1959 (to account for those that rejected consolidation and didn't join the new UUA; another one of those histories) and onwards?