Several parodies sung to "Hark..." Three are in Hymns and Carols of Christmas," linked above.

There have been several translations of the six verses of "Silent Night" as transcribed by Joseph Mohr. Our usual verse 2 is a free translation of verse 6.
The repeat of the last two lines of each verse (with different notes) is seldom done.
Original music by Gruber including the repeats (with audio) and text for verses 1, 2 and 6 (not 3) here: Stille Nacht