Here is the full list of all 35 GRIP achievements worth 1,000 gamerscore. It takes around 50-60 hours to unlock all of the achievements on Xbox One.
Finish the tutorial
Finish a race
Finish a 20 lap race
Race 50 laps in total
Race 250 laps in total
Race 1000 laps in total
Finish 1st in a race
Finish 1st 3 races in a row
Finish 1st 6 races in a row
Go from 10th to 1st within one lap
Average a speed 700kmph+ in a race
Hit 3 opponents with a charged RamRaider
Destroy an opponent
Finish an arena match
Hit Mach 1 in a race
Destroy 2 players without dying
Destroy 3 players without dying
Destroy 4 players without dying
Destroy 50 opponents
Destroy 100 opponents
Destroy 250 opponents
Finish a carkour course
Finish all carkour courses
Finish the campaign
Create a custom tournament
Pull a wheelie on the ceiling
Land a with a Scorpion when you are airborne
Hit an airborne opponent with the Scorpion
Perform a double-somersault when airborne
Make a hit with a round of Raptor bullets
Hit only cars with salvo of Hydra missiles
Destroy some scenery
Win by passing the leader in the last second
Hit 3 or more opponents with a single Hydra
Destroy 5 players without dying