Ahzidal's Armor is a unique set of ancient Nord armor found in Dragonborn. Despite being identical to ancient Nord armor in appearance, it has a higher base armor rating and weighs more. Ahzidal's armor matches steel plate armor in terms of armor rating.
Ancient Nord Armor is a set of heavy armor that appears in The Elder Scrolls V: Skyrim. It is a variant of the iron armor set and has similar base attributes, though it is slightly lighter, and benefits from the Daedric Smithing perk, vastly increasing its armor rating when improved.
Daedric Armor is a set of heavy armor available in The Elder Scrolls V: Skyrim. It is extremely heavy, but also has the highest armor rating in the base game and its add-ons. The armor set contains five pieces: a helmet, boots, gauntlets, a cuirass and greaves, and an optional shield.
Dawnguard Heavy Armor is a set of heavy armor that appears in The Elder Scrolls V: Dawnguard. It is worn by members of the Dawnguard, who are an order of vampire hunters. Neither of these unique enchantments can be disenchanted and applied to other items.