The final Booster Course pass DLC, wave 6, is coming to Mario Kart 8 Deluxe on Switch this holiday. The final expansion will include Daisy Circuit courses and add four drivers. None of the drivers are completely new as they have appeared in previous Mario Kart games, but you will be able to race as Funky Kong, Diddy Kong, Pauline, And Peachette.
Source: Game Informer Funky Kong, Diddy Kong, Pauline, And Peachette Are Coming To Mario Kart 8 Deluxe