To Hear Your Banjo Play is a documentary by Alan Lomax from 1947. It is narrated by Pete Seeger and features Woody Guthrie, Sonny Terry, and Brownie McGhee among others.
Wade Mainer played a two-finger style of banjo, between old timey and bluegrass. Here is an interview he did with David Holt at the age of 97. Part 2. Part 3. Still playing strong!