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
Found all Pulp Magazines
Completed the Collection
Found all 'Gangsters of the United States' cigarette cards
Found all copies of Gangsters Monthly
Completed the game on Classic difficulty
Found a Mystery Fox
Took Paulie to a Place of Disrepute
Performed a wheelie for 3 seconds
Lost the cops after accruing a five star police chase
Resisted arrest by the Lost Heaven Police Department
Reached 50mph while driving the Bolt Ace
Found all of the hidden cars
Found a hidden car
Collected 30 vehicles in the Garage
Paid a fine to the Lost Heaven Police Department
Lockpicked 5 cars on the streets of Lost Heaven and environs
Completed "The Death of Art"
Completed the game on Easy, Medium, or Hard difficulty
Completed "Moonlighting"
Completed "Just For Relaxation"
Completed "Election Campaign"
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
Found a 'Gangsters of the United States' cigarette card
Completed "Molotov Party"
Found a Pulp Magazine
Completed "Running Man"
Completed "An Offer You Can't Refuse"