The 5.2 PTR is now open and available to players, however most of the new Pet Battles features have not been implemented yet.
That doesn't mean the PTR doesn't have any neat information for pet collectors, though! The Pet Journal has been updated to include the three pets that were datamined towards the end of December. Here's a sneak peak at what's to come.
New TCG Pet
The Gusting Grimoire will be the common pet loot card from the upcoming TCG expansion, Betrayal of the Guardian. This new set is scheduled to be released in February of this year.
The Gusting Grimoire shares a similar look with the Lofty Libram, however unlike the Lofty Libram, the Grimoire has a different color scheme as well as slightly different Pet Battle attacks.
Possible Raid Dropped Pet
The second datamined pet is the Living Sandling. This interesting elemental companion is a drop from within the Throne of Thunder, according to the Pet Journal.
Wowhead categorizes the Throne of Thunder as a raid zone, so could this pet be the first pet to drop from current raid content? For now, we can only wonder which boss or creature it might come from!
Elite Battles Reward
Last but not least is the Red Panda. This crimson colored critter is listed as the reward for completing a quest. Currently the quest has not been implemented, however the nature of the quest was already revealed in the official 5.2 PTR patch notes.
"Elite Battle Pets" have a chance to spawn in the wild. Rather than a team of three, a player's pet team will face off against one elite pet! These new encounters will be part of a quest, and completing it will reward the Red Panda.
The Red Panda might still be a work in progress since it's currently classified as a humanoid with multiple humanoid attacks similar to the Curious Oracle Hatchling. We'll see if this pet receives any updates in the next PTR build.