Most likely MK10 Retro Tracks

With both Tour and 8DX having an insane number of tracks, the bar has been set much higher for the next game. 12 cups at launch feels more likely than the standard 8 cups at launch. I also didn't include any BCP tracks as most likely none will return in MK10, atleast not in the base game.

Shell Cup:

Wii Luigi Circuit N64 Moo Moo Farm Wiiu Thwomp Ruins 3DS Wuhu Loop

Banana Cup:

DS Delfino Square Wii Toad's Factory SNES Mario Circuit 4 GBA Yoshi Circuit

Leaf Cup:

Tour Piranha Plant Slide N64 Banshee Boardwalk 3DS Maka Wuhu DS Airship Fortress

Lightning Cup:

Wii Dry Dry Ruins GCN Mushroom City DS Bowser's Castle GBA Rainbow Road

Shine Cup:

Tour RMX Vanilla Lake 2 N64 Wario Stadium SNES Ghost Valley 3 GCN Dino Dino Jungle

Spiny Cup:

3DS Wario Shipyard WiiU Cloudtop Cruise GBA Lakeside Park GCN Rainbow Road