I created a chart of the non-wild, pre-MoP pet qualities (as seen on the 5.1 PTR), but my toons have outdated collections on the PTR. I'm missing some pets so my list is incomplete.
If anyone (on the PTR) has any details about the quality of the missing pets, please let me know! Also, if you notice any incorrectly listed pets, let me know. Chart can be viewed here
Missing pets (I'm guessing all Darkmoon pets are rare):
Fetish Shaman (rare?)
Mini Diablo (rare?)
Murkimus the Gladiator