Bob Dylan, yes. Nobody else connected with the folk revival in Britain, ireland or north America. And of actual traditional folk performers, none. Pretty much by definition. The folk create perfect music that reflects society. Genius creates revolutionary art that attacks and changes(though the art may be constructed from folk ingredients). Different things.
Genius always seems to be separated by a generation or so from the folk from which it springs. Dylan stood away from his folk background, as did Louis Armstrong and Duke Ellington, the two shining examples of jazz geniuses. jazz was a folk music in New orleans in 1900, but the time Armstrong and Ellington had given it a bit of a going over in the 20's, it wasnt folk any more!