The Four Temperaments Of Elves

One peculiarity of Tolkien's reinvention of Northern European mythologies is that it appeared in several distinct forms: the "children's fiction" of The Hobbit (along with some similar early poetry), the high fantasy Lord of the Rings trilogy, and the elaborate mythology laid out in the Silmarillion and other unpublished works. The result is that the reinvention of fantasy staples like "elves" and "dwarves" created not just a single depiction, but a number of competing presentations. Elves in The Hobbit are frivolous and wild merrymakers, while elves in the trilogy are noble warrior-sages.

Mucha, The Four Seasons

While the setting of Middle Earth creates an explanation for why elves come in different varieties, I think the basic idea of elves being divided by history and genetics is less interesting than the idea of them being divided by temperament. In a game setting, no one has enough time to listen to a long discourse on the history of your pseudo-Tolkienesque elves. But the personality types are immediately obvious. I've grouped them by "season", which seems appropriate for a nature-oriented magical race.

Vernal Elves
Vernal (springtime) elves are lighthearted and full of nonsense. They love jokes and jests, and are prone to singing and dancing. They are sanguine and make for pleasant company, at least for those with a tolerance for their foolishness. They are hard to motivate, and tend toward the vice of frivolity. (Example: Rivendell elves in The Hobbit)

Estival Elves
Estival (summer) elves are seekers of pleasure and leisure. They love wine, feasts, and hunting, and favor epic poetry and romantic ballads. They are skilled at entertaining, although they often dislike the intrusion of uninvited outsiders.  They are boastful and stubborn, and tend toward the vices of arrogance and passion. (Example: Elves of Mirkwood in The Hobbit)

Autumnal Elves
Autumnal (autumn) elves are melancholy, weighed down by sorrow and longing. They secret themselves away in distant forest groves, either dreading change or else seeking a quiet reconciliation with the loss it brings. They are wise and noble, and have a fondness for ancient lore. But they are tragic, living in a world of fading dreams, and prone to the vice of despair. (Example: Galadriel and the elves of Lothlorien in the trilogy)

Hibernal Elves
Hibernal (winter) elves are brooding and intense, and are susceptible to anger or jealousy. They value craftsmanship and warfare, and are quick to take offense and slow to forgive. They make for powerful allies, but fearsome enemies. They are prone to the vices of cruelty and vengeance. (Example: The Noldor, particularly Feanor and his sons, in The Silmarillion)

Again, these aren't subraces or species of elves, but elves of a given personality type and philosophical outlook. In a fantasy game world where elves are often found in the same geographical regions as fey creatures, it would make sense that these tendencies would emerge not genetically but from contact with that aspect of the faerie realm. Vernal elves would be influenced by the company of playful sprites and pixies, estival elves would make their homes amid lusty satyrs and centaurs, autumnal elves would prefer to live near dryads and nymphs, and hibernal elves would be hardened by living a constant state of war with sinister fey like boggarts and formorians.

In my own game world setting of Proxima, I imagine that these classifications are explicit -- so that someone could actively refer to a group of elves as "Elves of the Summer Court", and everyone would know exactly what that meant.