Ness' design is so relatively plain and old-school, I enjoyed watching everyone's eyes light up at his image only to come to the crushing realization that they had no fucking clue who he was moments later.
Elsa:
Extremely well-developed character in a movie many people loved
Rosalina:
Star Princess
(This is coming from a Super Mario Galaxy worshipper, mind you. I don't think Rosalina had nearly enough lore)