Starting with We Love Katamari, you could play as The Prince's cousins if you so wish. There are so many playable characters in this series. Ichigo is my all-time favorite cousin, but she isn't the only one who I really like!! Here are all of my favorite cousins!!
The Prince
Ichigo
June
Opeo
Ace
Dipp
Kuro
Daisy
L'amour
Twinkle
Huey
Macho
Paula
Mu
Nai-Nai
Princess
Pu
Mag
Harvest
Mint