Sherclop Pones found these out in the wilds of the Internets and sent them in. They’re the clothes horse horse clothes for the Rainbow Dash and Pinkie Pie plushies.
Rainbow’s looks like the various dresses she wears in the show, mostly the gala dress.
Pinkie is wearing a very glittery ensemble with some sort of collar/neck thing.
The plushies won’t be up for sale until April 1, though they’re already in stock in the back of many stores and have displays up to create hype. The heads seem to be pre-stuffed and you’re only filling up the body/legs.
+10 childhood points if you know where clothes horse horse clothes comes from.