5. 10, or 20? You kidding, Ms. Jo? You want any old folky to narrow down to less than a hundred?
Dylan: "Blowing in the Wind", "Don't Think Twice"
Tom Paxton: "Ramblin' Boy", "Can't Help But Wonder Where I'm Bound",
             "Home to Me".
Anne Hills: "Follow that Road", or the ancient "Never Grow Old"
             recorded with Cindy Mangsen.
Gordon Bok: "The World is Always Turning T'ward the Morning"
Kingston Trio, "Tom Dooley"; (the first time I ever realized there
             was something called folk music)
Horse Songs? How about Cisco Houston singing "Zebra Dun"?
I even remember some gal with long blond hair singing "All Around My
         Hat" on television...