At the moment I am running with Clockwork Robot (9), Core Hound pup (10) and just started levelling my Proto Drake Whelp (5) as a third pet since I didnt like my Coral Snake
Clockwork Robot is a boss. Very strong damage pet with DoT, strong single target attack and the sticky grenade is a game changer if used strategically. The passive is awesome to because he comes back to life when killed which has actually helped me win a few PvP battles.
Core Hound Pup is amazing! Insane damage and combined with his Howl that makes the enemy take 100% more damage for 2 rounds it is just crazy. Hit enemy pets for nearly three quarters of their health at times and he is actually quite tanky.
Proto Drake Whelp is my newest edition to my team because I wanted a good pet that could fly. He has pretty awesome damage, can fly to avoid the next attack and has a pretty big heal that he unlocks at level 15 so overall I am pretty happy with my team.