What is an example of an archetype?
Tarzan, Sherlock Holmes, James Bond and Conan the Barbarian are all archetypes.
Some of the best characters come from the worst writers, because good writers avoid writing archetypal characters and bad writers do so without hesitation.
An archetype is the ultimate version of a character type. They aren't the first or the best, but they are the purest because they are uncluttered by realism or deep characterization.
Ian Fleming's James Bond, 007 is far from literature's first spy. Joseph Conrad's "The Secret Agent" had him beat by a good 50 years; Milady from Alexandre Dumas' The Three Musketeers beat him by over a century. Spies are mentioned in the Old Testament. But Bond was Ian Fleming's fanciful self-image of the glamorous, hard-drinking, womanizing hero he liked to present himself as having been during World War II, and very little in Fleming's actual record supports this characterization. Bond was to Fleming as "Red Rascal" is to Doonesbury's Jeff Redfern.
Tarzan's literary lineage is a little bit more distinguished. He had elements of Mowgli (Rudyard Kipling's The Jungle Book) and Rousseau's "natural man," as well as the real-life Wild Boy of Aveyron. Edgar Rice Burroughs took this stock character--the wild man who is pure of civilization's corrupting influences--and made him a serial action hero.
Archetypes are appealing because they are so unconflicted by the dross of real life. One could scarcely imagine Philip Roth writing Alexander Portnoy in such a manner, or John Updike depicting Rabbit Angstrom as such. Only a bad writer tackles such characters with the gusto required to make them so delicious. Great writers, sadly, know better.