It’s very simple.
Get Boneshard from Lord Marrowgar in ICC.
Get Ikky from Spires of Arak first few quests.
Get any hard hitter pet (like mine Chrominius with Howl and Surge of Power to finish the job)
then…
Boneshard goes first, use Blistering Cold in 1st round, in 2nd use Chop then spam Ice Spike till Boneshard dies.
Choose next pet which is Ikky, use Black Claw on his first round, and flock in second.
If boss is not dead yet after flock (or Ikky dies) you can Howl + Surge boss to finish the job.
Ikky debuffs from black claw and flock + blistering cold stacking dot + howl + surge of power = insane dmg dealt to a boss.
That works excellent unless boss has insane rng with crits.