For the Grand Prix, I doubt there will be new courses, with Mario Kart Tour having mostly retro courses. At least there will be 12 cups with 48 courses (four courses for each cup). There's going to be some Wii U courses because I want to keep antigravity, and there's 5 difficulties (50cc, 100cc, 150cc, Mirror, and 200cc). Also, I have the courses sorted by which console they debuted on (from SNES to Wii U). Click one of the three buttons for courses and cups.
Credit to all. Mario Kart belongs to Nintendo. Images from the Super Mario Wiki. (I worry that some of my picks might be controversial.)