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.
Found all Mystery Foxes
Completed the Collection
Found all Pulp Magazines
Found all copies of Gangsters Monthly
Found all 'Gangsters of the United States' cigarette cards
Completed the game on Classic difficulty
Took Paulie to a Place of Disrepute
Collected 30 vehicles in the Garage
Found all of the hidden cars
Lockpicked 5 cars on the streets of Lost Heaven and environs
Found a hidden car
Resisted arrest by the Lost Heaven Police Department
Reached 50mph while driving the Bolt Ace
Performed a wheelie for 3 seconds
Found a Mystery Fox
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
Collected 15 vehicles in the Garage
Completed "Crème de la Crème"
Completed "You Lucky ..."
Paid a fine to the Lost Heaven Police Department
Completed "Happy Birthday"
Completed "Bon Appétit"
Completed "Great Deal"
Completed "Visiting Rich People"
Completed "Omerta"
Found a copy of Gangsters Monthly
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 'Gangsters of the United States' cigarette card
Found a Pulp Magazine
Completed "Molotov Party"
Completed "Running Man"
Completed "An Offer You Can't Refuse"