The 6.2.1 PTR is up and running, and there are three new manafiend pets. [source]
In the upcoming patch, three new rare elites can be found in Nagrand.
Travel to Highmaul and enter the non-instanced area to find three rare elite ogres, each of which has a chance to drop a different pet (pictured above).
List of all 6.2.1 PTR datamined pets
According to Blizzard Watch, the pets are personal loot and are not guaranteed to drop. All three manafiends are Bind On Use and can be caged.
Stay tuned to find out if Patch 6.2.1 will have even more pets to collect!
Patch 6.2.1 PTR: Three New Pets
July 16, 2015