Here is the full list of all 43 Mafia: Definitive Edition achievements. It takes around 20-25 hours to unlock all of the achievements on Windows.
Completed "The Death of Art"
Completed the game on Easy, Medium, or Hard difficulty
Collected 15 vehicles in the Garage
Completed "Just For Relaxation"
Completed "Moonlighting"
Completed "Election Campaign"
Lost the cops after accruing a five star police chase
Completed "Crème de la Crème"
Completed "You Lucky ..."
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"
Found a copy of Gangsters Monthly
Completed "Better Get Used to It"
Completed "Sarah"
Completed "Fair Play"
Won the race
Completed "Ordinary Routine"
Found a Pulp Magazine
Completed "Molotov Party"
Found a 'Gangsters of the United States' cigarette card
Completed "Running Man"
Completed "An Offer You Can't Refuse"
Paid a fine to the Lost Heaven Police Department
Resisted arrest by the Lost Heaven Police Department
Lockpicked 5 cars on the streets of Lost Heaven and environs
Reached 50mph while driving the Bolt Ace
Performed a wheelie for 3 seconds
Collected 30 vehicles in the Garage
Found all Pulp Magazines
Found all copies of Gangsters Monthly
Found all 'Gangsters of the United States' cigarette cards
Found a hidden car
Found all of the hidden cars
Found a Mystery Fox
Found all Mystery Foxes
Completed the Collection
Took Paulie to a Place of Disrepute
Completed the game on Classic difficulty