There was a time -- and perhaps that time continues, but it's hiding if so -- when some leading "free" (itself often shorthand for free-thought, ethical-basis, or "post-Christian") churches were not in Unitarian or Universalist fellowships. Proudly independent they were. Think Fountain Street Church, but peppered over the land.
And I found another example while looking through old hymnals, this time Out West: the Free Church of Tacoma, Washington. Long gone -- the current Tacoma Unitarian Universalist Congregation dates to 1944 -- it leaves behind a journal (Google Books) and that hymnal. (Hymn list)