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 Fairytale Land 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 series's 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.

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. 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.

Fairy Magic
Fairy Magic works differently from other types of magic in which it requires a reagent. This reagent, called Fairy Dust, is obtained by enchanted creatures called Dwarves. 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 was lifted and Rumplestiltskin unleashed Magic upon Storybrooke, the fairies were left powerless due to the absence of Fairy Dust. However, the Seven Dwarves were capable of finding diamonds which Mother Superior planned to use to make Jefferson's hat work again.

Fairies are able to fly and beeing summoned by someone's wish. The Fairy Magic includes magical abilities such as the transformation of objects or beeings, including themselves' size.

The Fairy Dust, in the other hand, gives them the abilities of accelerating a dwarve's birth, and puting people to sleep.

Witchcraft
Witchcraft is a form of magic that makes use of spellbooks 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, and making objects appear out of thin air. Significantly, they can create and/or cast curses, such as Dark Curse and the Sleeping Curse. Wichcraft practitioners can also perform acts of transformation over themselves or someone else, create protective shields. They can also perform acts negative to another being such as cousing 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. They can also cause physiologically impossible situations, such as cutting someone's head without killing him or having   healing powers. In addition, they can also summon creatues such  as a Wraith.

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's trapped inside a mirror (because of his desire to be with the Evil Queen and seeing her face everyday), he now has the ability spying and appearing through mirrors.

Science
Science is the most recent addition to the list of forms of magic. This "Science", however, 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
 * Blue Fairy
 * Fairy Godmother
 * Nova
 * Rumplestiltskin / Mr. Gold (with wand)
 * ​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
 * Science
 * Victor Frankenstein / Dr. Whale