Armor of training: has no AC, but gives you a small multiplier to your experience point gains (and possibly skill point gains) whenever you are wearing it.

FIQhack has added this, but as an object property rather than a new object.

Ring of carrying: new chargeable ring that multiplies the weight of the player’s inventory by (1 - (0.05 * enchantment)) when worn. Stacks with a second ring. Initial charge and beatitude is set the same as any other charged ring.