The good people over at Petopia have posted a lot of new info about pets seen on the PTR for 2.1. First, there's been four new pets found so far-- a new Blackwind Warp Chaser, a Ravager from Hellfire Peninsula, the Sky Shadows in Deadwind Pass (that scared the heck out of you even before the expansion was released), and this amazing purple tallstrider called a Dodostrider (that last one has hunters buzzing).
One pet will be made untamable-- apparently there are issues with the Death Ravager that gets spawned in a quest in the lowbie Draenei area, Azuremyst Isle, and so hunters won't be able to tame him any more. Also, Petopia has PTR info on two new trainable pet abilities, Avoidance and Cobra Reflexes. Avoidance has two ranks and reduces the damage done to pets by AoE (this is aimed directly at endgame PvE pet viability), and Cobra Reflexes has one rank and increases attack speed at a cost to damage done.
As usual, all this info is still subject to change. But it's great that Blizzard is getting more and more pets (and pet abilities) in the mix. Here's hoping the trend continues.