These are the five silver dragons in Val’sharah who drop either a pet or toy.

Darkshade at Ravencourt in Black Rook Hold drops the Risen Saber Kitten

Gorebeak (summoned by Lorel Sagefeather in Whispering Bluffs) drops the Pygmy Owl

Pollous the Fetid (summoned by Filandras Mistcaller in Dreadroot) drops the Fetid Waveling

Old Bear Trap (on the RS of the road from Bradensbrook) summons Mad Henryk who drops the Worn Doll

Sersei in Wretched Hollow (southwest of Thas’talah) drops the Cursed Orb
Have I missed one? Let me know in the comments below.
I think Val’sharah is shaping up to be my favourite zone so far, I mean it’s got this lot… need that Worn Doll by Hallows End, Harpies and a pretty awesome quest chain.
I thought you’d like that. :P
Accidentally got myself killed though getting to Sersei since I inadvertently ran through an Alliance camp.