The wearer of a Circlet of Iron Necromancy can control twice the normal HD of undead, and when calculating damage inflicted by their Life Tap ability, they factor in bonuses from both Wisdom and Intelligence, instead of selecting one or the other.

A Robe of Many Eyes has many symbolic eyes sewn into its exterior. When worn, this robe enables a conscious, unimpaired person to see 360° at all times. Effectively, the character cannot be caught flat-footed, and only surprised if magic or some extraordinary ability makes this possible. A person who sleeps in this robe will be warned of anyone approaching her with harmful intent, by the robe shocking the wearer awake (doesn't harm the wearer). Wearers of such a robe get a hefty bonus (DM's decision) on Notice rolls.

phylactery — a magic item of great expense and power which binds a lich's spirit, should the lich's body be destroyed, and permits the body to reform in a matter of days so that the spirit may rejoin it.

Unless its phylactery has been destroyed, a lich cannot be permanently defeated.