Here is the full list of all 15 Blaze and the Monster Machines: Axle City Racers achievements.
Win a race in split screen
Unlock all the STEM images
Win the First 10 Races
Unlock the first STEM image
Finish the Adventure
Participate in Final Adventure
Win The third Championship
Win The second Championship
Win The first Championship
First Race Win
Step on a boost pad 30 times
Use special skill 10 times
Finish The Tutorial
Use a Special Skill for the first time
Play a 4 player split screen race