With WoW's 13th Anniversary event bringing back the old Vanilla WoW bosses refreshed for Level 110, they also brought back their old items. Some of these have unique appearances that have been lost to time since those world bosses were removed. I've listed all those unique appearances below, what boss to get them from and who they are for.
Happy hunting!
Item Name Boss Slot Deviate Growth Cap Lethon Leather Head Gauntlets of the Shining Light Lethon Plate Gloves Polished Ironwood Crossbow Emeriss Crossbow Boots of the Endless Moor Emeriss Mail Boots Circlet of Restless Dreams Emeriss Leather Head Acid Inscribed Pauldrons Ysondre Plate Shoulders Leggings of the Demented Mind Ysondre Mail Legs Nightmare Blade Taerar One Hand Sword Unnatural Leather Spaulders Taerar Leather Shoulders Boots of Fright Taerar Leather Boots Acid Inscribed Greaves Shared Loot for Above Plate Boots Dragonspur Wraps Shared Loot for Above Leather Bracers Hammer of Bestial Fury Shared Loot for Above One Hand Mace Fang of the Mystics Azuregos One Hand Dagger Unmelting Ice Girdle Azuregos Plate Belt Typhoon Azuregos Two Hand Sword Sapphire-Encrusted Tunic Lord Kazzak Leather Chest [Alliance PvP Replica, unavailable to Horde normally] Empyrean Demolisher Lord Kazzak One Hand Mace Amberseal Keeper Lord Kazzak Staff