Earth ponies have no wings or unicorn horn, and therefore most closely resemble real ponies. They are the kind first introduced by the My Little Pony brand. The chapter book "Twilight Sparkle and the Crystal Heart Spell" mentions that one special trait is "the strength of a good, true heart of an Earth Pony." The main cast of the show My Little Pony Friendship is Magic features two Earth ponies: Applejack and Pinkie Pie.
Earth ponies were the original ponies to be featured in the My Little Pony toy line. According to Lauren Faust , Earth ponies have a special connection to nature, animals, and plants. Though they lack the ability to consciously cast spells like unicorns or to fly and walk on clouds like Pegasi, their connection to nature makes them "just as necessary" as and "perhaps more important" than the other ponies.
In the chapter book Twilight Sparkle and the Crystal Heart Spell, it is written that Twilight Sparkle, from the moment she becomes an Alicorn in the episode Magical Mystery Cure, "was now able to harness the magical powers of the Unicorns, the flight abilities of the Pegasi, and the strength of a good, true heart of an Earth Pony."