I will exclude Opera and Broadway singers. My list would include singers and singer song writers:
Sinatra,Crosby,Armstrong,Mathis,Sammy Davis Jr,Tony Bennett,Bobby Darin, Ray Charles,Bobby Short,Orbison,Elvis,John and Paul, Simon and Garfunkel, James Taylor and Billy Joel.
Sinatra,Crosby,Armstrong,Mathis,Sammy Davis Jr,Tony Bennett,Bobby Darin, Ray Charles,Bobby Short,Orbison,Elvis,John and Paul, Simon and Garfunkel, James Taylor and Billy Joel.