Daisy and Waluigi.
Both are nothing but fillers in Mario sports games. It's true that Daisy appeared in the ending of a Super Mario platforming game many years ago, but just that.
I would even say Pauline is more revelant than those two by far. Her presence as the major of New Donk City, managing the recovery of the city after the attack, organizing a festival, and continuing to maintain the city doing all her best for the best of the citizens, made her a very interesting character.
Hey! Daisy has an amazing single