Archfey (ark-fey)

Archfey were fey beings who gained nearly god-like powers and established a position of preeminence among fey-kind. Each archfey had a unique appearance and set of abilities, most controlled a portion of the Feywild and had self-proclaimed titles. Some of them were powerful fey of many races, others were the awakened spirits of natural places such as forests or rivers, others the sentient incarnations of different types of animals, and others were noble eladrin so old and powerful they transcended the bounds of mortality.
Some archfey were regarded as deities and granted divine abilities to their worshipers. Archfey could be contacted by a willing warlock to form a fey pact.
Archfey were difficult to kill, for each one had a nemesis- an item, special condition, or creature- that could slay it, but only the nemesis could destroy them. Nemeses were unique to each archfey.
Notable Archfey:

Baba Yaga, Mother of All Witches

Hyrsam, the Prince of Fools

Neifion, the Lord of Bats

Nintra Siotta, the Princess of Shadow Glass

Oberon, the Green Lord

The Prince of Frost

Queen of Air and Darkness

The Stag King, a dark fey who dwelled in Rashemen.

Titania, the Queen of the Seelie Court

Verenestra the Oak Princess

Kannoth, the Vampire Lord of Cendriane

Zybilna, the Ruler of Prismeer and the patron of the Witchlight Carnival

Additionally, the deities Auril (under the name of Aurilandür), Relkath, Sarula Iliene, and Lurue were considered by some as archfey in the late years of the 15th century DR.