Elf

Most elves live far longer than humans, but it's unclear exactly how much. Eladamri was over 150 years old and considered to be in his prime. Ravnican elves not only live far longer than humans but also mature faster; it is unknown if this is common to all elves or just those of Ravnica.
Elves can be found in virtually every plane throughout the multiverse. To date, Amonkhet, Kamigawa, Ixalan, Ikoria, Mercadia, Rabiah, Tarkir, Theros, and Ulgrotha are the only natural planes to have no known races of elves, and only small portions of some of these have been seen. Elves were once present on Innistrad, but were driven to extinction.

Elves of Alara

While the Shards of Alara were separated, the Cylian elves only inhabited Naya, but after the Conflux they are free to roam the whole plane again. The nomadic Cylian elves live in the tree canopy and gather around dewcups, pools of water that form in the canopy's giant ferns. There are many of these oasis-like gathering places in the canopy, and it is here that the elves camp. Led by Mayael the Anima, the elves worship the gargantuans of the plane. The elves believe that the behemoths' actions are signs from Progenitus, an enormous five-headed hydra who sleeps under the ground in the Valley of the Ancient. The elves constantly monitor the steam that rises from three vents on the floor of the valley, which they believe to be the breath of Progenitus himself, for signs of his stirring.
Godtrackers are warriors who track the movement of the gargantuans through the jungles and mountains. They ignore all territorial boundaries and tend to stir up fights with humans and nacatl wherever they go. The best warriors of the elves, they will kill anything that gets in the way of tracking a gargantuan. They report back regularly to Mayael.
Epicists write epic accounts that record the behavior and battles of the garguantuans based on reports from Godtrackers. This oral art form is the historical memory of the elves, and one that allows Mayael to better understand the will of Progenitus.
Valley Wards constantly watch the Valley of the Ancient and monitor Progenitus' breathing from treetop camps spread throughout the valley. Alone for days at a time, valley wards communicate with each other by playing music on wooden pipes. These haunting tunes echo across the misty valley and are a language understood only by those who devote their lives to serve as stewards of a sleeping god.

Elves of Ravnica

The Erstwhile

The Erstwhile is an ancient faction of elvish aristocrats that were entombed in the modern Undercity. The Golgari have unearthed their coffins and reanimated them as part of the Swarm. They still wear their stately attire, despite its moldering condition, and they lend an air of high culture to the undercity court of the Golgari.

Devkarin Elves

Devkarin are the dark elves of Ravnica. Formerly, they made up one of the two elite classes of the Golgari, the other being the teratogens. They are presided over by their "Matka", a high priestess, who until recently was Savra. The current Matka is Izoni, Thousand-Eyed. The Devkarin are adept spellcasters counting most of the Golgari's shamans among their numbers. Some of the Devkarin wear Moodmarks, which are minor enchantments that appear as spots or markings on their foreheads and around their eyes (usually resembling insect eyes).

Silhana Elves

The Silhana are the Ravnican elves that are part of the Selesnya Conclave. The Silhana are master archers who stalk the rooftops of the city-plane. Some Silhana, the Elves of Deep Shadow, were cast out of the Conclave long ago and joined the Golgari.

Simic Elves

There was once a third tribe of elves on Ravnica, one that became largely extinct during the pre-Guildpact wars; the survivors joined the Simic Combine. Little is known about them, but both the Devkarin and the Silhana believe they were very cruel and unpleasant. Simic elves seem to have been mostly bald. As time went by, almost all of the Simic elves subjected themselves to strange biological experiments, adding biomechanical implants or splicing their genes with those of other creatures, such as snakes.

Elves of Zendikar

The elves of Zendikar are a highly adaptive race that makes their homes in the treetops of Murasa and Bala Ged. Natural risk-takers, the elves have a strong survival instinct and fearless demeanor, making them well suited for life on this dangerous plane. They lack a formal religion, instead, they practice forms of mysticism as well as communing with the spirits of their ancestors.

Joraga Nation

The Joraga Nation was seated in the Tangled Vale portion of Bala Ged. Their leader was Speaker Nen, although the various tribes were only loosely connected. Each tribe followed the migratory pattern of a particular species of beast, adapting the creature into their magic and combat styles. Nomadic by nature, the Joraga eschewed outsiders and held even the other elves of Zendikar in disdain. With the coming of the Eldrazi, the Joraga were nearly eliminated.

Mul Daya Nation

Mul Daya was a secretive nation located in the Guum Wilds of Bala Ged. They could easily be recognized by their facepaint and tattoos. While their living leader was Hazzan, he himself followed the edicts of a centuries-old elvish spirit named Obuun. Through their leadership, the Mul Dayans became adept spies and assassins with the elite calling themselves "vine ghosts." Mul Dayan Soulspeakers openly practiced a blend of mysticism and necromancy to better commune with their ancestors. Special brakeguards were the only tribe members who could safely navigate the wilds.
Like the Joraga, most of the Mul Daya were wiped out by the Eldrazi.

Tajuru Nation

Through the leadership of Speaker Sutina, the Tajuru nation had become the largest and most prominent elf faction on Zendikar. Basing society within the massive treetops of Murasa, the Tajuru were open to other races and highly skilled innovators. Their capital was the Tumbled Palace based on the cliffs of Sunder Bay. Before the creature died in the tentacles of Kozilek, Sutina often had been seen overlooking the water just before Lorthos, the Tidemaker appeared. Any connection between the two remains unknown. A later leader of the Tajuru was Nisede.

The Kazandu Splinter

The Kazandu Splinter is a small separate faction of elves located in Kazandu region of Murasa. Formerly Tajuru, they broke off from the nation refusing to see Speaker Sutina as their leader. Their life on the dangerous cliffsides and in the jaddi-trees has fundamentally changed their outlook from their former brethren.