Looks like Tee shirts and blindbags are the dominant force in the pony world. That may be due to the amount of them we have. Hopefully those future collector sets keep expanding on the molded ponies!
Onward to the next poll! This one is a bit complicated. We have a ton of characters in FiM if those Comic Con promo posters are any indication. A good amount of the one-shots or "every once in a while" characters enter and leave before we really get to know anything about them. Discord for example seems to be an ancient equestrian evil, while Zecora is a complete enigma.
I'm not including fan named characters, but if I missed a canon character that you think needs some explainin', feel free to pick other.