You can find here a comprehensive listing of the Penguin Maigret editions that I have found very useful. Scroll down to see the titles and images of the latest Penguin Classics issues.
A chronological English checklist of the 75 Maigret novels, with variant titles and year of original French publication is here.
The dates the Maigrets were published are generally known. Exactly when and where the Maigrets were written is not as clear… The 103 novels and stories listed here comprise all the Maigrets published under Simenon’s own name.
The First Maigret Novel