The “continuing Congregationalists” are probably the closest relatives to the Universalists (probably) apart from the Unitarians, so it’s worth to look at their resources.
The National Association of Congregational Christian Churches has a page of worship resources, especially ordinations and installations. There’s a 1978 book, The Congregational Worshipbook, that’s now out of print but can be downloaded. I’ve held it and read from it before, and do not recommend it. An absolute brick, and a bit too particular to its author. Do you really need services with the particular anthems filled in? The very specific dedication services (a Bible? a window? a pulpit?) is the flip side to this particularity and maybe the most useful part of the book.