Artus Moser? Appalachian singer. Horton Barker. Great Appalachian singer. Nimrod Workman, also. All were singing in the Sixties. Hally Stepherson Wood. (Married to John Henry Faulk). Mary O'Hara wasn't well known in the States but big in Ireland. Orla Fallon reminds me of her.
Art Thieme knows Bill Chipman...a great country voice...not unlike Riley Puckett.
Sam Eskin lived in Woodstock N.Y. and was a folksong collector and songwriter.
Blues musicians not too well known....Big Joe Williams (not of Count Basie fame). I mentioned Snooks Eaglin earlier. A great player and singer from N.O.
Joseph Spence was singing and playing from Bahamas in the Sixties. "Blind" Blake (not Arthur Blake) was from the same area and nobody knew much about him at the time.
You know Sandy Paton might be included. Everyone knows him for his Folk Legacy but he was a fine interpreter of British Isle ballads.
My friend Dave Zeitlin from L.A. teaches guitar at McCabes and sang and performed well.
Also my friend Guy Carawan and his wife Candie...major contributors to folk music as folklorists and sociologists.
Lee Haring banjo folkie from N.Y.
All I can think of now.