While this is overly simplistic, if you're looking for the better breeds, consider this:
The H/H, P/P, & S/S breeds have the biggest bonuses.
Breeds with two stats listed (P/S, H/S, & H/P) are next best.
Breeds with one stat bonus (P/B, H/B, & S/B)
Balance (B/B) is your "ah crap, I got a balance" bottom feeder.
The reason it's overly simplistic is because some specific uses for a pet require particular features. For example, the Unborn Val'kyr
comes in Balance B/B (everything gets a small bonus) and Guardian H/H (health gets a large bonus.) If your intent is to Curse of Doom
followed by Unholy Ascension
, then the extra health is useless. You're committing suicide on the second turn. You want damage, and the B/B (292) has more power than the H/H (276).
But for the most part, the rule of thumb should help guide you.