Artifact suit of armor (type is unspecified, perhaps a ring mail or chain mail) that is unaligned and operates like magic armor in the Legend of Zelda. When worn, it drains your gold at a constant rate, and when you take damage, you lose a somewhat randomized amount of gold, in exchange for partially or completely negating the damage (perhaps the easiest way to do this is via half physical damage, since it doesn’t make much sense for armor to protect against e.g. poison damage from drinking a potion of sickness). Gold is consumed at some rate higher than 1 per turn, and it is lost for damage at some rate higher than 1 per hit point.

If you have no gold while wearing it, you become either very slow or very encumbered, and it ceases to reduce or negate damage.

Croesus may occasionally generate wearing this armor, along with some gold to supply it. Otherwise it generates like any unaligned artifact.

Artifact cloak of invisibility Death’s Embrace, which grants phasing, immunity to death effects, and half physical damage, but reduces speed.

An unaligned artifact amulet versus poison which also confers sickness resistance, half physical damage, and raises Constitution to 25 when worn. Tentatively named “The Eye of [something]”.

Shimmering dragon scales or scale mail should grant half physical damage in addition to displacement because anything that hits you is likely a glancing blow due to the displacement.

Chargeable ring that reduces incoming damage (perhaps by half, not triggering if half physical or half spell damage applies from some other source) but may lose a charge every time you take damage.

The Heart of Ahriman grants half physical damage, and Thoth Amon is nearly guaranteed to pick it up.