My list is down to a few hard to get pets:
Ethereal Soul Trader
I am willing to trade both things I have only one of as well as the things I have extras of for deals involving these items.
Pets I currently have one of but could be talked into trading: Level 25 Bananas, Hippogryph Hatchling, the four pandaran spirit pets, all the raiding with leashes pets, Darkmoon Eye, Level 21 Darkmoon Rabbit, Rare Sapphire Cub, Rare Gilnean Raven. (The bananas, hippogryph hatchling, darkmoon eye, and darkmoon rabbit I am only willing to part with if the deal involves a soul trader since I have only one of each).
Others not as notable: the various holiday / reputation pets, black tabby cat, common TCG pets such as the Eye of the Legion.
My battle tag if someone is interested in working something out is Vasala#1465. (Basically I am a person with little money but a fair amount of time so I am willing to re farm pets but don't have the cash to buy stuff for real money. So I am seeking someone with the cash but not the time since as the goblins say time is money friend.)