Playing their own game...
Mario Kart 8 Pack 1 - Released: November 2014
Pack 1 includes:
3 Characters: Tanooki Mario, Cat Peach, Link
Mario Kart 8 Pack 2 - Released: May 2015
Pack 2 includes:
3 Characters: Villager, Isabelle, Dry Bowser
As a bonus for purchasing both packs - as a bundle or separately - you can get eight different-coloured Yoshis and eight different-coloured Shy Guys that can be used right away.