Here is the full list of all 16 Toybox Turbos achievements. It takes around 2-3 hours to unlock all of the achievements on Windows.
Earned 1,000,000 coins
Achieved a 3 star rating for every event in the game
Played an online match against any opponents
Collected all vehicles
Beat all boss battles
Completed an event on every track in single player
Achieved 3 stars in a Countdown event
Achieved 3 stars in an Escape event
Repainted any vehicle with a custom colour
Unlocked a new cup
Achieved a 3 star rating for every event in a single cup
Achieved 3 stars in an Overtake event
Purchased any vehicle
Achieved 3 stars in a Time Trial event
Achieved 3 stars in a Classic race
Played a local match with more than 1 player