I'll give up a few secrets here, since I've been seeing them around elsewhere.
The most successful team I have this patch:
Unborn Val'kyr (b/b because that's all I can find) 1,2,1
Crow (p/s) 2,2,2
Alpine Hare (s/s) 2,2,1
The timing between the rabbit and the val'kyr is amazing. I generally will only use CoD on mechanicals or monstrous tanky pets (1700+ health), then haunt. In comes the rabbit to dodge, attack, burrow. At that point the CoD goes off if it was applied, and the next round, when the rabbit re-emerges, the valk hits the back ranks again. Swap for the valk and repeat unless the rabbit can one-shot the other guy. I've had matches where the crow isn't even used--but he's extremely important to counter aquatics with shell shield and to go toe to toe with other flyers and guys faster than my rabbit. An amazing team. I saw Snow post an identical team on the WoW forums the other day, so figured it was finally time to bring it up here. I've only ever run into one mirror match, and that was a h/h valk, so mine was faster and haunted first, his died when it tried to haunt the same round. b/b has its advantages.
Occasionally I'll run into someone with a good counter, like an emperor crab with shell shield and a magic attack pet like a dragon or broom. That combo can give the above a really hard time. Or more valks than you can shake a stick at, which can be extremely interesting, but at the same time, I just want my wins. Team B is
Death Adder Hatchling (s/s) 1,1,2
Emperor Crab (p/p) 2,2,1
Lil' Tarecgosa 1,1,2 (Thanks again to
Deal With It on Shadowmoon)
This team is fairly strong, but it really shines when the meta has put up counters to the valk team above. The crab takes like 5 pts damage from haunt and can easily out heal most incoming damage. That guy alone will wreck a valk team that has no flyers. And if they do, the dragon will counter flyers even when they're in the back ranks, and hurts magic pets hard. Surge tears apart elementals, and the DAH is just op, so why not? Again, I see the most success with this team when there are a lot of valks and magic pets queuing up. It's far from perfect, but when every team has a valk on it, it wins a lot.
My other teams I play for variety's sake that are still competitive are
Darkness
Crow (p/s) 2,2,2
Searing Scorchling 2,2,1
Ghostly Skull (h/p) 1,2,2)
Conflag
Harbinger of Flame 1,2,2
Silver Dragonhawk Hatchling (s/s) 2,2,2 (a throwback to the FFF days)
Searing Scorchling 2,2,1
Other teams with reasonable but not top tier win records are
Bling Dancer
Unborn Val'kyr (b/b) 1,2,1
Jademist Dancer (s/s) 1,2,1
Lil' Bling 1,1,1
Moonlight
Fungal Abomination 1,1,1
Nether Faerie Dragon (p/p) 2,1,1
Xu-Fu, 1,1,2)
And the 5.3 terror that is still pretty effective, Change-Up
Fiendish Imp (s/s) 1,1,2
Giant Bone Spider 1,2,2
Stunted Direhorn 1,1,1 (sometimes I'll throw the Enchanted Broom in for the Direhorn and make them all changers)).
All of these teams are pretty strong against my battle group. ymmv.
*edit: penguin, crab, same thing, right?