The Manic Pixie Dream Girl is sort of a dated/dead trope now, because the trope name came up in response to the sheer number of movies in the 00s that effectively had the plot:
"David is a beleaguered office worker/salesperson who has long ruled out his childhood dreams of [something creative and kind of childish], but when Rainbow crashes into his life, her cooky charms shake up his dull routine and teach him and his stuffy friends to embrace chaos and fun!"
But like how the term "Mary Sue" gets used for any female character who shows any level of power and competence on par with or greater than any male character, even just one specific skill she has a good reason to be good at, it quickly started being applied to like... any slightly quirky female character rather than this very specific trope of "female character who is painfully quirky in a 'not like otha girls' way whose plot role is based entirely around bringing out the innate awesomeness in a male character" so....
The guy who coined the term has disowned it. (His reasoning is pretty much what I just said; in the 00s, these plotlines were eeeeverywhere, but the term gained steam pretty much as the actual trope was fading away).
Of course, this hasn't meant the end of the related action/fantasy/sci-fi trope of: "Hyper-competent woman who has trained her whole life meets some average useless guy and helps him to realise his magical chosen one powers and surpass her in a very short period of time and isn't annoyed in the slightest that he now gets to be king/god/the true kung-fu master/head wizard." Which is still, as always, alive and well.