Adding to the list (now with Archfey):
Yeenoghu, Demon Prince of Gnolls (Level 28 solo, Dragon #364)
Mual-Tar, the Thunder Serpent (Level 35 solo, Dragon #370)
Alloces, the Butcher of Nessus (Level 28 elite, Dragon #373)
The Prince of Frost (Level 31 solo, Dragon #374)
Koliada, the Winter Witch...