I base my experience around my 1700+ pvp wins. By FAR my most successful pet has been my Blossoming Ancient. He can solo most teams he goes against, so I bring other pets that synergize with him well, like a moth to counter aquatics strong against the tree, and whatever other pet I think will go wel...

Blossoming Ancients' Sunlight kills the decoy and hits one backline pet. That combined with its hot and damage reduction makes it strong against most other non healing pets.