In Winterspring, theres an area called Lake Kel'Theril where Anguished Highborne's are.
Formula: Enchant Weapon Icy Chill - BoE, Requires 285 Enchantning.
Anguished Highborne - Level 55-56, 2,823 - 2,915 HP ( I could usually get them down with 2 Arcane Explosions).
They have about a 4% chance to drop the Formula for Icy Chill. I can usually get about 10 of these in the hour, and depending on the server you can sell them anywhere from 15g-100g each. The Anguished Highbornes are the only ones that drop them and they are all around that area.
Enjoy
Edited for color![]()