Note: Image heavy. Over 20 images! They're not super HD awesome quality, but it's good enough for just a taste. If you use WoWModelViewer, I'm sure you could find these new companions in there somewhere. :)
Also remember that this is the PTR so pets are still a work in progress, and some may change over the course of this testing period.
Last but not least, pay no attention to the colored border around each pet's icon. The PTR Pet Journal is slightly buggy and will show all pets as the same quality.
New Wild Pets:
Anodized Robo Cub (mechanical) - Winterspring
Arcane Eye (magical) - Deadwind Pass
Cogblade Raptor (mechanical) - Blade's Edge Mountains
Crow (flying) - Darkmoon Island
Emerald Proto-Whelp (dragonkin) - Sholazar Basin
Fluxfire Feline (mechanical) - Dun Murogh
Harpy Youngling (humanoid) - Northern Barrens
Honky Tonk (mechanical) - ??
Infinite Whelpling (dragonkin) - Caverns of Time
Kun-Lai Runt (humanoid) - Kun-Lai Summit
Lofty Libram (magical) - Hillsbrad Foothills
Nexus Whelpling (dragonkin) - Coldarra (Borean Tundra)
Stunted Yeti (humanoid) - Feralas
Sumprush Rodent (beast) - Krasarang Wilds
The new crow pet looks just like the raven, however it's slightly lighter in color.
There's currently no source listed for the Honky Tonk, so we'll have to wait on that one.
Oh, and sorry about the Infinite Whelpling. It seems as though it's shy and wants to hide, even in the Pet Journal. :P
New Raid Boss Drops:
Mr. Bigglesworth isn't pictured above because we all know what he looks like, right? He shares the same model as the Siamese Cat. Although he looks like a cat, he's actually part of the Undead pet family.
For a list of which raid bosses these companions will drop from, see this post.