On Warla's site, http://schaffhauser.me/Warcraft#PetBreeds (are they still censoring this link?), you can see the possible rarities that pets come in, based on armory profiles. So you can see which of the pre-MoP uncommon pets that people have chosen to upgrade--I was surprised at how many different pets have been upgraded by at least somebody out there (ie somebody upgraded an Orange Tabby Cat, a Black Kingsnake, the vendor moths, etc etc).
So far, I have only upgraded Willy so far. He's my avatar, a Magic-based pet, and he's just a fun pet. Granted, he's only 4 right now, but I have high hopes for him.
On the horizon, if I can ever get another one, would likely be: Legs (Another great Children's Week magic pet. Has strong attacks.) Baby Ape (Between this and Giraffe Calf for most frustrating so far, but Baby Ape wins because I have only ever seen one, and it was Poor quality. My Giraffe Calf is at least Common, and I still see them from time to time.)
I also want to upgrade Personal World Destroyer, but he didn't make the cut because I already have Mini Thor, Lil' XT, and a rare Tiny Harvester, which feed my mechanical powerhouse needs at this time. I'd hate to waste it on something that is too similar to something else.
My top 3 would be Minfernal, Scourged Whelpling and either Jade Owl or Mecha Panda Dragon.
Probably the MPD.
I do have to admit to using a Dragon stone on an Emerald Proto-Whelp since the best I ever found was a poor.
How funny that you say this as the only 2 stones I've got so far are 1 Beast (used for Baby Blizzard Bear) and 1 Dragon which I used for Emerald Proto-Whelp as the only one I've seen so far and captured was, like you, poor.
Scourged Whelp. I'm tired of hunting, and I've found a lot. Just never a rare. So that will leave more in the world for others to find
So far I've upgraded Minfernal, Infinite Whelp, Harpy Youngling, Crow, Red Cricket, (and a beast and an aquatic I can't remember). I have a Magic stone, I think I'll use on the Jade Owl and a non-specific one for the Scourged Whelp. A little afraid to use it, thinking I'll get that family in my next bag, but sometimes you gotta take the big chances
Morgannath wrote:I haven't found any pet stones yet, is there a trick to it?
I have gotten BoP random family stones from grand master dailies, and gotten a flawless non BoP non family specific stone on a random wild pet battle in Pandaria. You also have a chance to get family specific BoP stones for doing battles with any pets in the world, though the higher the level, the higher the chance. So fighting a frog in Pandaria will give a chance at a BoP aquatic stone, etc.
I would go for one that is hard to find, never mind getting a rare. If you can get a rare by simply keep checking then don't do it. I have 2 myself, and I'm saving one for that rare in Felwood, and possibly my Nexus Whelpling.