Widge: You named Hamlet after its main character.
Shakespeare: Well, this is not Hamlet. More's the pity.
If the Protagonist Title is also a pun, it's an Epunymous Title. If the title also includes the protagonist's occupation, it's Role Called.
See also Protagonist and Friends, Character Name and the Noun Phrase, The Full Name Adventures, and Mononymous Biopic Title. Compare to Antagonist Title, contrast with Secondary Character Title. Subtrope of Character Title.
Since this is such a common convention, please don't list examples on this page.