And, yet again, fellow bronies, the conversation steers back to Derpy, the most famous background pony of the lot.
FANMADE Derpy Got Swag

Derpy the Fan Celebrity

Though not a main character in the show, Derpy Hooves is one of the most frequently seen background ponies.
FANMADE Filly Derpy wearing a tiara

Behold Derpy- crowned as the Most Famous Background Pony of all Equestria!

Often seen as one of Rainbow Dash's close friends, other than the rest of the main six, Derpy is a Pegasus pony with a light butter yellow mane and tail and a gray coat, with a few bubbles as her Cutie mark. Her special trait is her crossed eyes- which is why she was named 'Derpy'. Derpy is even more popular than some members of the main six among the fandom (i.e. Applejack and Rarity).

Perhaps it's because of her cuteness- or maybe because of her strange Derpy look- but by some Research by the Comments (checking the comments, in simpler English), I saw that some of the commenters have even threatened to stop watching MLP if Derpy isn't there in Season 4! Some of them want Derpy to have her own Element of Harmony, but I say that we leave Derpy where she is. She might be the most famous background pony, nonetheless, but she is, after all, just a background pony.

P.S. Let me get this straight. Some commenters below think that want Derpy to join the Main Six. Let me tell you- that is a downright lie. Thank You. I just wrote the title of the blog because she's almost as popular as the Main Six. Right? If you ever took the time to visit my page, you must've seen that I hate Derpy.