Charlie or Charley, Chas or Chaz, Chuck or … Chuck. Also, oddly enough, Chip.
Famous people named Charles:
Prince Charles of Wales; actors Charlie Chaplin, Charlie Hunnam, and Charlie Carver; musicians Chuck Berry and Charlie Parker; basketball player Charles Barkley; naturalist Charles Darwin.
Charles Phillip Ingalls (a.k.a. Pa) was the father of author Laura Ingalls Wilder, and one of the main characters in her true-life Little House on the Prairie series.