There's no best pet in my opinion. Any pet is only as good as the talents you hatch into them. That being said, the pet's personal extra cards can make a big difference. The extra Sharpened Blade cards given by Enchanted Armament makes it a great 'base' pet to hatch talents into for general play, both for attack and support. It's especially useful because it gives you access to Sharpen on lower level worlds rather than waiting until you are level 86 and halfway through Azteca. Makes soloing a lot of bosses early on MUCH easier.
The best pet in game is based a lot on your own personal opinion, whether you want a damage, resistance or healing pet.
However, the Sea Dragon has a lot of desirable traits (such as may cast Sprite, Spell Proof, and Pain Giver) and can be a good starter hatching pet, with a pedigree of 72.
