I have hundreds, and probably well over a thousand dollars' worth, of eighteen to twentieth century Universalist imprints slowly gathered over the years. I got each new title as I could -- first through specialist book dealers then eBay plus gifts -- because they are so hard to come by, and one chance of buying any given title might be the only one I got.
Then Google and a number of major university libraries changed all that. It is very encouraging to see these old titles scanned and made available. I guess my hand-transcribing days are behind me (and good riddance.)
There are so many titles available, and Universalist ones in particular, that I don't know where to start. A personal favorite, Menzies Raynor's 1839 The Universalist Manual: or book of prayers and other religious exercises is largely a prayer book adapted for lay use, and the kind of all-in-one book that got a lot of Universalist churches started independently. (Raynor was an Episcopalian before a Universalist minister.)
A nice touch: the digitized copy, from Harvard, was given by Thomas Whittemore.