Magic

"Magic always comes with a price, I know."

- Henry to David Nolan Magic is a metaphysical force seen on ABC's Once Upon a Time. It can be used to override the usual laws of nature, but it always comes with a price. Magic is inherently neutral and cannot be split between light or dark, although it is used for those purposes.

Price of Magic
Magic always comes with a price. The most famous price is Rumplestiltskin's curse, turning him into an almost heartless monster. His price is the heaviest shown so far, making him childish, eccentric and hideous though he lost none of his mental capabilities.

Other prices include the Evil Queen sacrificing her father to unleash her wrath upon the Enchanted Forest and creating a void in her soul that she can never fill. The most recent was when Mr. Gold brought magic to our world, which returned his powers, but also put a barrier around Storybrooke which prevents him from leaving to find his son.

True Love
"True Love is the only magic powerful enough to break any curse."

- Mr. Gold to Emma Swan

True Love is the series' baseline magic, available to anyone and can be used through a kiss. It is the most powerful form of magic and also the most simple. According to Rumplestiltskin, true love can do anything and break any curse with a kiss. It also transcends realms, as Emma used it in Storybrooke before magic from the Enchanted Forest was brought.

Rumplestiltskin sought to bottle true love and used hair from Snow White and Prince Charming to create a true love potion. This potion was kept in Dragon Form Maleficent's belly for protection. Later, his Storybrooke counterpart, Mr. Gold, would throw the potion into the wishing well and unleash its magic upon the small town.

True Love includes magical abilities such as breaking any curse. It is known to break any curse that has been seen so far, such as the Dark Curse. One of its powers includes reversing the effect of any negative witchcraft, such as a forgetfulness potion and even the physical abnormalities Rumplestiltskin got from his powers. As some practicers of witchcraft can rip out another person's heart, those born as a product of true love have the power to resist that magic. True Love also has the ability to extract and view memories with the help of a dream catcher.

Fairy Magic
Fairy Magic works differently from other types of magic in that it requires a reagent. This reagent, called Fairy Dust, is obtained by enchanted creatures called dwarves. In some cases of advanced magic, the Fairy Dust must be used through a wand. The Dwarves' purpose is to dig diamonds from the local mine. These diamonds are then smashed to make Fairy Dust which the fairies use then to practice their magical art.

After the Dark Curse is lifted and Rumplestiltskin unleashed Magic upon Storybrooke, the fairies were left powerless due to the absence of Fairy Dust. However, the seven dwarves are capable of finding diamonds which Mother Superior plans to use to make Jefferson's hat work again.

Fairies are able to fly and being summoned by someone's wish. The Fairy magic includes magical abilities such as the transformation of objects or beings, including their own size and telekinesis of inanimate object.

The Fairy Dust, on the other hand, gives them the ability to accelerate natural processes such as a dwarf's birth, to put people to sleep, is able to freeze and leave a being with an incredible amount of Witchcraft such as the Evil Queen temporary powerless, and to break the Yaoguai curse.

Dark Fairy dust, however, has only been seen transforming "deadly foes" such as trolls into cockroaches.

Witchcraft
Witchcraft is a form of magic that makes use of spell books and spells. When used, witchcraft often gives away a pink/violet glow and/or puff of smoke. Witchcraft seems to be a darker form of magic as all those who use it have either been corrupted or turned evil.

Witchcraft includes magical abilities such as telekinesis, which enables lifting and throwing people and objects, teleportation of oneself or others, making objects appear out of thin air and turning things invisible. Significantly, they can create and/or cast curses, such as Dark Curse and the Sleeping Curse. Witchcraft practitioners can also perform acts of transformation over themselves or someone else, or even create protective shields. They can also perform acts negative to another being such as causing them pain, immobilize them or make another being explode. They can even change the basic nature of something, such as spinning straw into gold. They also have the ability to make potions with various effects and enchant objects to have special functions. They have the ability to activate a portal, such as the hat or with magic beans. They can also cause physiologically impossible situations, such as cutting off someone's head without killing him or using healing powers. In addition, they can also summon creatures such as a Wraith.

Siren's Magic
The Siren is able to transform herself into any woman a man desires.

Genie's Magic
At least the Genie of Agrabah had the power to grant three wishes to the man who "woke him" from his lamp. However, since he is trapped inside a mirror (because of his desire to be with the Evil Queen and seeing her face everyday), he now has the ability of spying and appearing through mirrors.

Science
It is the Land Without Color's form of Witchcraft, but it is feeble, neglected sort of stuff. "Science",  would be considered Pseudoscience in our world due to some of its elements (bringing people back from the dead, for instance) being impossible by natural causes. Practitioners of Science have the ability to bring someone back from the dead by putting an enchanted heart into the body's chest. ("The Doctor")

Practitioners

 * True Love
 * Belle
 * Prince Charming
 * ​Emma Swan
 * Prince Phillip
 * Mary Margaret Blanchard
 * ​Fairy Magic
 * Snow White (with Fairy Dust)
 * Blue Fairy / Mother Superior
 * Fairy Godmother
 * Nova
 * Rumplestiltskin / Mr. Gold (with wand)
 * Belle (with Fairy Dust)
 * ​Witchcraft
 * Zoso
 * Rumplestiltskin / Mr. Gold
 * Cora
 * The Evil Queen / Regina Mills
 * The Blind Witch
 * The Mad Hatter / Jefferson
 * Queen of Hearts' Executioner
 * The Giant
 * Trish
 * Maleficent
 * Unnamed Wizard
 * Emma Swan
 * Genie's Magic
 * The Genie of Agrabah
 * Siren's Magic
 * Siren
 * Science
 * Victor Frankenstein / Dr. Whale