Here is the full list of all 50 MotoGP20 achievements.
Complete 25 multiplayer races
Win a race at Laguna Seca in Grand Prix or Championship mode
Win a race at Donington in Grand Prix or Championship mode
Unlock every Rider and Team in Historic Mode
Unlock 40 rewards in Historic Mode
Unlock 20 rewards in Historic Mode
Win 10 races in Historic Mode
Unlock 10 rewards in Historic Mode
Win a race in Historic Mode
Complete 25 valid laps in Time Trial mode
Complete 5 valid laps in Time Trial mode
Win the MotoGP™ Championship in Career mode as a rider
Complete at least 3 valid laps in a Winter Test session in Career mode
Win the Moto2™ Championship in Career mode as a rider
Reach the Qualifying objective 20 times in Career mode
Win a race at Valencia in Grand Prix, Championship or Career mode
Reach the Race objective 20 times in Career mode
Win a race at Sepang in Grand Prix, Championship or Career mode
Win a race at Phillip Island in Grand Prix, Championship or Career mode
Win a race at Motegi in Grand Prix, Championship or Career mode
Win a race at Buriram in Grand Prix, Championship or Career mode
Win a race at Aragon in Grand Prix, Championship or Career mode
Win a race at Misano in Grand Prix, Championship or Career mode
Win the Moto3™ Championship in Career mode as a rider
Win a race at Silverstone in Grand Prix, Championship or Career mode
Win a race at Spielberg in Grand Prix, Championship or Career mode
Win a race at Brno in Grand Prix, Championship or Career mode
Win a race at KymiRing in Grand Prix, Championship or Career mode
Reach the Race objective 10 times in Career mode
Reach the Qualifying objective 10 times in Career mode
Win a race at Assen in Grand Prix, Championship or Career mode
Win a race at Sachsenring in Grand Prix, Championship or Career mode
Complete 10 multiplayer races
Complete 5 multiplayer races
Complete your first multiplayer race
Win a race at Catalunya in Grand Prix, Championship or Career mode
Win a race at Mugello in Grand Prix, Championship or Career mode
Win a race at Le Mans in Grand Prix, Championship or Career mode
Reach the Race objective 5 times in Career mode
Reach the Qualifying objective 5 times in Career mode
Complete 10 Development Tests in Career mode
Win a race at Jerez in Grand Prix, Championship or Career mode
Obtain access to Qualifying 2 in Grand Prix, Championship or Career mode
Win a race at Termas in Grand Prix, Championship or Career mode
Win a race at Austin in Grand Prix, Championship or Career mode
Complete 10 races with Tyre Wear and Fuel Consumption in Grand Prix, Championship or Career mode
Complete 5 Development Tests in Career mode
Win a race at Losail in Grand Prix, Championship or Career mode
Obtain the Pole Position in Grand Prix, Championship or Career mode
Complete a Development Test in Career mode