Can't recall the order but first was probably a Burl Ives 78; others were "Folk Songs and Ballads" by Susan Reed, "American Songbag" by Carl Sandburg, "Six Songs for Democracy", and some Josh White, Leadbelly and Richard Dyer-Bennet.
First LP's were 10-inchers from the Folkways catalogue, Wade Hemsworth, Walt Robertson, Wallace House, Pete Seeger, Woody Guthrie.