These magical beings are found everywhere in the world of Hyrule although they are fond of woods the most. Fairies typically look like tiny Hylians with two antennas and wings, like a butterfly's (or sometimes a dayfly) in form but transparent. However, the actual body of a fairy is not easy to see because they usually shine with a bright light that can vary in color. Also fairies like to dress themselves with leaves and petals or sometimes small clothes. Things change when speaking of Great Faeries: they can alter their shape through magic, but as the name suggests, Great Fairies usually look like almost gigantic Hylians, easily twice their height (but they can choose to be just as tall as one too). Regardless of these changes in appearance, they seem to conform to each other all the times. Great Faeries have been seen with long braids and dressed in leaves, with flowing gowns and majestic butterfly like wings, as dark grey skinned women with four arms and no pupils, and even with the same aspect of common fairies, only of different size. While a Great Fairy's magic is far greater than that of others, this kind of fairy appears to be bound to special ponds of their own (but truthfully, little ones also love such places). Above the Great Fairies is the Fairy Queen, who may take a form of her own (sometimes that of a child) or look the same as the Great Fairies. There also is a strange phenomenon known as the "Fairy's Spirit", a large orb of light that heals on contact, not much else is known about it as it's a rare occurrence. On a side note, people are often led to believe that faeries are only female, and while this is not the case, it would certainly seem for male faeries to be few in number and hardly (if ever) make it to Great Fairy status.
Faeries use magic with the same ease as a man can walk, but small ones are restricted to certain talents, the large majority of them being healers while some have different abilities (and are completely incapable of healing). It also appears that the Four Spirits of Seasons are fairies too, as were the three Spirits serving the Ocean King, and as a matter of fact, most other beings need for a Great Fairy to unlock their inner magic power before they can practice magic themselves. Fairies are (except the few mischievous ones) very caring and they like to help kind and honest people with whatever magic they specialize in. The large majority of fairies can cure others with magic, and although this leaves all but the Great Fairies exhausted, they will never refuse to help a good person, even if they were previously put into a bottle or some other container, which faeries greatly dislike (and which makes them slightly wary of people). Additionally, it is not too uncommon for artefacts to be enchanted with fairies' magic.
Legend has it that Faeries can live for thousands of years and through the ages, they certainly have played an important role in the history of Hyrule and other lands, as they have been of assistance to all of the heroes who appeared through the generations. Most importantly, a fairy guided the Hero of Time through his journey, and fairies granted him and the Hero of the Winds powerful spells, they gave the Silver Arrows (Ganon's only weakness) to the Hero of Legend, and opened the path onward for the Hero of the Essences and that of Four Swords. The heroes often returned these favors, like when the Hero of Time helped the Great Fairies that SkullKid had shattered to be whole again, or when by defeating Ganon the Hero of Legend returned Venus the Fairy Queen to her original shape. Fairies also helped look after the children of the Deku Tree, the Koroks, when they took the form of children and became Kokiri (possibly the fairies themselves where the ones who changed the Koroks). Speaking of which, there seems to be definitely a connection between fairies and blessed woods, seeing as a butterfly can become a fairy if touched with a Deku Stick; which would lead us to believe that fairies and certain forest trees share a symbiotic relationship.