So I imagine many others are like me: I refuse to spend money on the game.
That instantly makes Blizz store and TCG pets unavailable.
But Battle Pets allow most of these to be caged and sold on the AH!
However, before Battle Pets you could filter the store by what you can use and have it auto-ignore all the pets you have, only showing the few (if any) you do not yet own.
Post Battle-Pets, this is not possible.
So I am wondering if there is an addon which returns this capability to the AH, or at least lets you sort by Max Quality Owned (placing none owned in a section below poor, and allowing an ascending sort by that column to quickly reveal new things, as well as making it easy to locate better quality upgrades)