Piano was used by Sandy Denny, Joni Mitchell, Dylan and lots more. Personally I don't llke it in folk - better in jazz - Mcoy Tyner & Herbie Hancock are two faves. In Rock/pop Nicky Hopkins was king. But folk ... can't really imagine it around the campfire, mind you I did like the old pub singalongs - used to be a great one down Walworth Road (London)in the late sixties/early seventies can't remember the name of the place but it was huge (for a pub) with a huge crowd gathered , all singing along to "Boiled Beef & Carrots" and the like.