I couldn't find any other wedding-related historic Universalist collects (family illness and travelling seem to be a more pressing concern) to celebrate the weddings beginning today in Massachusetts, but I did find this lovely prayer to share.
We praise and bless Thee, O Lord, for the joy of thankfulness and devotion, and for the peace which ever flows through patience and comfort of Thy holy word.
The earth is full of the riches of Thy goodness: the gospel is full of the riches of Thy grace: and all Thy perfectoins, and all our blesings, meet in the commandment to love Thee with all our heart.
O let Thy mighty power descend and inspire us, that our spirits may become emblems of Thine; and endue us, we beseech Thee, with wisdom from above, that we may turn many to righteousness, and shine as the stars of the firmament for ever and ever. Amen.
- From "Prayers after Sermon" in Gospel Liturgy (New York: Henry Lyon, 1861), p. 61.