Black Velvet Band (7)
Johnny I Hardly Knew Ye (infinite versions/variations of this)
Sweet Violets (another with infinite versions--plenty of room for improvision)
Maids When You're Young Never Wed an Old Man (at least 3 versions)
Foggy Dew (I think there may be 2 songs with this title, but it seems that each has about 3 variations)
Peace--Keli