Two new pets were added in the latest 6.2 PTR build — Cinder Pup and Shard of Cyrukh. [source]
The Cinder Pup (pictured right) will be a reward from a follower mission, Fiery Friends.
"A group of tiny fiery puppies was spotted deep within Blackrock Foundry. If we save them, we may be able to raise them."
We hope the Cinder Pup will get along well with the Cinder Kitten!
List of all 6.2 PTR datamined pets
The second pet, Shard of Cyrukh (pictured left), will require a fair amount of questing in Tanaan Jungle before gaining access to the area in which the treasure spawns.
According to Twitter user @Mononic1, the treasure containing the Shard of Cyrukh is located south-east of Throne of Kil'jaeden. Once this area is unlocked for you, keep an eye out for a glowing yellow crystal jutting out of the ground (pictured below).
Update On Crusher
Crusher, a pet inspired by the ideas of a seven year old aspiring developer, was added to the PTR.
This pet will be available from Trader Araanda (A) and Trader Darakk (H), found inside the Town Hall in your garrison. Crusher will cost 1000 gold and is Bind on Use.
True to the boy's original concept art, Crusher wields a little pickaxe when summoned out (pictured right).