I have always been fond of folk music. Cat Stevens was a favorite. Although Donovan reached his peak popularity in the 60''s his best album in my estimation was a two record set, HMS Donovan, his most poetic and literate album. It had virtually no airplay in the US unfortunately. The entire album is avalable on You Tube. The best cut is The Voyage of the Moon. Mary Hopkin''s Postcard album also has an exquisite rendition of the Voyage of the Moon with Donovan and Paul McCartney on guitar.
In respect to Christian music from the 70''s Daniel Amis comes to mind especially Shotgun Angel. 'Some of the later albums, Including other incarnations of the band The Swirling Eddies, Lost Dogs,and solo albums by Terry Taylor, especially Knowledge and Innocence have also been exceptional. I do have a problem with sone of the content however.
Phil Keaggy has also had some outstanding albums.