As reported early October of this year, the next TCG deck will be Timewalkers: Betrayal of the Guardian. The release date is set for February 12, 2013. Cryptozoic recently made the official announcement for this upcoming TCG expansion, but did not list the loot cards for it yet.
Many online card game vendors are still showing a "Floating Spellbook" as one of the loot cards, and since the other two don't sound like a possible pet, it would seem as if this will be the common pet for Betrayal of the Guardian.
I wouldn't be surprised if this is indeed the pet for the upcoming deck, since there's now a spellbook pet model (Lofty Libram). My only hope is that they make the TCG spellbook companion a bit unique either in color, model, or battle abilities. It's understandable if they want to re-use an existing model to save time, but at the very least throw on a new skin, yea? :P
But who knows. Maybe things will change and the Floating Spellbook was just a placeholder. We'll have to wait and see!