Huey, Dewey, Louie and Scrooge McDuck
from wikipedia:
Colors of Huey, Dewey, and Louie's outfits
In early comic books and shorts, the caps of Huey, Dewey, and Louie were colored randomly, depending on the whim of the colorist.
On few occasions until 1945 and most every cartoon short afterward, all three nephews wore identical outfits (most commonly red). It wasn't until the 1980s when it became established that Huey is dressed in red, Dewey in blue, and Louie in green. Disney's archivist Dave Smith, in "Disney A to Z," said, "Note that the brightest hue of the three is red (Huey), the color of water, dew, is blue (Dewey), and that leaves Louie, and leaves are green." Another combination that shows up from time to time is Huey in blue, Dewey in red, and Louie in green. In-story, this inconsistency is explained away as a result of the ducklings borrowing each other's clothes.