|Thanks to MfG for the image!|
It looks like the alicorn yellow set is actually showing up as well as the special edition metallic/glitter ponies. This one specifically was bought at a store called Muller in Germany, and they have apparently been around for months.
|Thanks to Longneck for the image!|
And finally, the Hasbro Toy Shop apparently slipped a blue set out to Flutterawesome when they purchased the first wave box set off the website. I don't know if it was an accident, so I wouldn't rush over there hoping to get the metallic ponies, but it's worth noting!
I guess Hasbro is dropping these all over in no specific order! Your best bet is to keep an eye out!