A little experiment here.

The only thing I wanted was to see Fluttershy characterized as World, from Magical Drop III. Then I searched for images… and nothing. Much more, I couldn't find any MLP-Magical Drop crossover. I was very surprised.

Ideally, it would have been to make a commission… but I'm poor. The next (no ideal) thing: my own version. Thinking about it, I saw other character equivalencies, so I changed to do all the mane six. And then, I changed again to do all female characters from Magical Drop with some pony equivalent.

The problem is that I couldn't come up with a definitive equivalence; some are very evident for me, but others not so much, or not at all. This is the best thing I like, but I can see others versions or preferences.

For me, Twilight Sparkle, Applejack, Princess Luna, Rainbow Dash and Fluttershy are perfect crossovers. Pinkie Pie is good enough, although by subject Princess Candance makes sense. I'm not totally good with Rarity, but I guess you can look for connections (like being a diva). Celestia conection is only because Fortune is the final boss in the videogame. Death and Temperance as Starlight and Sunset I feel them very generic; nothing wrong, but neither perfect. And I can't think of anypony for Star: I though Moondancer or Marble Pie, but I I ended up using Sci-Twi.

What I'd like is for someone who does have real talent to end up doing their own versions. Take note and spread the word.