Here is the full list of all 43 Mafia: Definitive Edition achievements worth 1,000 gamerscore.
Completed the game on Classic difficulty
Found all Pulp Magazines
Completed the Collection
Found all Mystery Foxes
Found all 'Gangsters of the United States' cigarette cards
Collected 30 vehicles in the Garage
Found all copies of Gangsters Monthly
Found all of the hidden cars
Completed "The Death of Art"
Completed the game on Easy, Medium, or Hard difficulty
Completed "Moonlighting"
Completed "Just For Relaxation"
Completed "Election Campaign"
Lost the cops after accruing a five star police chase
Completed "Crème de la Crème"
Completed "You Lucky ..."
Completed "Happy Birthday"
Collected 15 vehicles in the Garage
Completed "Bon Appétit"
Completed "Great Deal"
Completed "Visiting Rich People"
Completed "Omerta"
Completed "A Trip to the Country"
Found a Mystery Fox
Completed "The Saint and the Sinner"
Completed "Better Get Used to It"
Performed a wheelie for 3 seconds
Found a hidden car
Lockpicked 5 cars on the streets of Lost Heaven and environs
Resisted arrest by the Lost Heaven Police Department
Completed "Sarah"
Completed "Fair Play"
Took Paulie to a Place of Disrepute
Won the race
Completed "Ordinary Routine"
Found a copy of Gangsters Monthly
Completed "Molotov Party"
Paid a fine to the Lost Heaven Police Department
Reached 50mph while driving the Bolt Ace
Found a Pulp Magazine
Found a 'Gangsters of the United States' cigarette card
Completed "Running Man"
Completed "An Offer You Can't Refuse"