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