There are the chants from the Graduale Simplex, also harmonized for SATB by Aristotle Esguerra and posted here at the MusicaSacra forum.
Also, I have a setting at CPDL of Parce Domine with Psalm 51, with the verses of Psalm 51(50) set in a triple Anglican chant. The Parce Domine (also set in English "Spare, O spare us Lord...") forms a part of the second Antiphon.
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