The next trio of WoW TCG loot will arrive in October of this year when the War of the Ancients expansion is released. An exact date has not been set yet.
Update: 09/10/12 — Timewalkers: War of the Ancients will officially release on October 2nd.
The mount loot is going to be the Feldrake. Based on its name you can conclude that it's a flying dragon mount. It is of course the ultra rare loot in this expansion – with approximate odds of 1 in 242 packs.
The novelty loot item in War of the Ancients is the Demon Hunter's Aspect. This loot item transforms its user into a Demon Hunter for 5 minutes, with a 30 minute cooldown.
The pet loot is the Eye of the Legion, which looks like the Warlock's Eye of Kilrogg spell.