I added in some characters I would have liked to have seen included, as well as other common suggestions.

This is what the roster would be, if Sumo Digital and Sega had common sense.

Team Sonic : Sonic, Tails, Knuckles
Team Dark : Shadow, Rouge, Omega
Team Rose : Amy, Cream, Big
Team Chaotix : Vector, Espio, Charmy
Team Silver : Silver, Blaze, Sticks
Team Babylon : Jet, Wave, Storm
Team Eggman : Metal Sonic, Dr. Eggman, Orbot & Cubot
Team Deadly : Zavok, Zazz, Zeena
Team Adventure : Tikal, Chao, Chaos
Team Classic : Classic Sonic, Classic Mighty, Classic Ray

https://www.deviantart.com/majestyfr/art/Team-Sonic-Racing-Extended-Roster-849567504