Archfey

An Archfey is a powerful fey creature with the influence, understanding, and power to bend the surrounding Feywild to its will. Most Archfey belong to the Seelie Court, the Unseelie Court, or one of the other courts, but may even be unaffiliated, like Artagan.

Known Archfey
The Arcana Pansophical was aware of five Archfey as of 812 PD, though one had been slain the previous year: Two other individuals are likely classified as Archfey:
 * Lord Artagan of the Morncrown Artagan-by-David-Rodrigues.jpg
 * Lord Saundor the Forsaken
 * Lady Elmenore the Unforgiving
 * Potentate Sammanar
 * Keeper of the Moontides
 * Naviask
 * Queen Titania of the Summer Court

Pre-Divergence
Before the Divergence, Artagan tricked a nascent civilization of elves into worshipping a whale carcass. This drew the ire of the elven god Corellon, who banished Artagan from the Material Plane.

Also before the Divergence, Naviask was a powerful balor bent on the destruction of the Feywild until he fell into one of Queen Titania's traps, and she transformed him into a fey spirit whose mission is to use nature to heal scarred lands.

Post-Divergence
After the Calamity, Naviask was drawn to the Material Plane to heal the devastation that war had caused.

Campaign One: Vox Machina
When Syngorn was in the Feywild during the Chroma Crisis, Artagan helped some fey, including a pixie prince named Windybranch, to slip through the city's defenses, where they occupied a noblewoman's manor and transformed it into a fun slice of the Feywild; she tried to reclaim her home for years afterward.

Artagan played an important role in Vox Machina's adventures. He guided Vox Machina on their quest to slay his fellow Archfey Saundor (which yielded Saundor's mighty bow Fenthras for Vex'ahlia) and when they retreated to the Feywild, he ensured they could get a full rest and stop Vecna before the lich's miracle of terror was completed. As part of the deal for his aid, Vox Machina built Artagan a doorway back to the Material Plane.

In the meantime, several members of Vox Machina had taken a vacation to the Feywild. Against Artagan's advice to avoid the Theater, they snuck in to watch a performance of the Royal Troupe of the Unseelie Court; at the end they saw an "entity" step back into a doorway, signaling it was time to leave; this entity was presumably Sammanar.

Campaign Two: The Mighty Nein
Artagan used the doorway Vox Machina built for him, and thereby became the childhood friend and patron of Jester Lavorre. Through his ongoing and evolving relationship with her, he guided the Mighty Nein throughout their campaign. He had amassed hundreds of followers, but wished to unburden himself of almost all of them. With the help of the Mighty Nein he gathered them all on the island of Rumblecusp in an event known as TravelerCon and tried to trick them into believing he had always been Sehanine in disguise. This went awry when one of that goddess's powerful servants appeared and nearly re-banished him.

As of 836 PD, Naviask's followers said he still wanders the wastes of Xhorhas, seen only by those whom he wishes to see him. He was by then an Archfey patron for warlocks, seeking those of a similar heart and offering them power to help heal the land.

Exandria Unlimited
Lady Elmenore had some kind of possessive relationship with the faun Fearne Calloway, but Fearne's grandmother helped Fearne travel from the Feywild to the Material Plane. During her adventuring party's travels, Fearne was drawn into a confrontation with a dark, more powerful version of herself wearing the Circlet of Barbed Vision, and this dark alter ego said the Warqueen wanted Fearne back. After the battle that followed, Fearne could feel Elmenore's displeasure at the dark alter ego's failure.

Trivia

 * Titania and Oberon from A Midsummer Night's Dream would be considered Archfey in the Critical Role setting.