Six Elements of Harmony exist and they are: Loyalty, Magic, Kindness, Generosity, Honesty, and Laughter
The Elements, as seen in the prologue of S01 E01.
The six ponies that bear the Elements of Harmony do not simply hold the elements, but embody them. Little is known about the true and full abilities of the Elements as of yet.
The Elements of Harmony, as shown in S02 E02.
Honesty
Held by Applejack. Applejack represented this element when she told Twilight to trust her and let go when hanging off a cliff. Twilight takes the risk and trusts Applejack, and is saved by Rainbow Dash and Fluttershy before hitting the ground. She demonstrates this element everyday with her dedication to her family, and her hard-working attitude.
Kindness
Held by Fluttershy. Fluttershy demonstrated this element by calming a Manticore in the Everfree Forest by showing it kindness. She demonstrates this element daily with her compassion towards all lliving things.
Generosity
Held by Rarity. Rarity first showed this element when she calmed a sorrowful Serpant by giving him her tail to complete his glorious moustache. Rarity demonstrates this element daily with her generous gifts to her friends, including gems, dresses, and capes.
Laughter
Held by Pinkie Pie. Pinkie Pie showed this element by calming down her terrified friends, teaching them to laugh at whatever scares you. Pinkie demonstrates this daily, by constantly filling her days, and those of her friends, with laughter.
Loyalty
Held by Rainbow Dash. Rainbow Dash showed this element first when she refused to abandon her friends, even when offered a spot as team captain of the Shadow Bolts. Rainbow demonstrates this element daily by always having her friends' backs, even if it means putting herself in danger.
Magic
Held by Twilight Sparkle. Twilight first showed this element when she realized how much she loved and cared for her friends. This realization caused a spark to light inside of her, activating the elements for the first time. Twilight shows this element daily with her vast skills with magic, and her care for her friends.