Axe of the Dwarvish Lords 27
Baba Yaga's Hut 18 -- Excellent adventure location, but not really an artifact. Besides, it's Russian folklore, not iconic D&D.
Codex of the Infinite Planes 25
Eye of Vecna 19
Hand of Vecna 8
Mace of Cuthbert 14
Machine of Lum the Mad 14
Rod of Seven Parts 27
Sword of Kas 26
Wand of Orcus 22