Mulligans
General Mulligans
After 10 turns,you actually burn your opponent, as far as you have your Dr. Boom's hero power(with pixie) , you have your combo (Voodoo Doll into Zola the Gorgon into a second Voodoo Doll into Whirlwind for a 2-minions removal {even minions that can't be targetted by spells or divine shield minions} and ,of course, you have your Omega Assembly, that draws you 3 cards that have Rush. You can skip Brawl or Dyn-o-matic if you want to add Magnetic combos.
Aggro Mulligans
Eternium rover is the new powerful class 1-mana 1/3 minion that is really powerful in a control or a mech deck. Shield slam is a (3) mana removal for 4 damage, to a Hench-clan Thug, for example. You can use Reckless Fury at 5 mana for 4 damage AoE.
Combo Mulligans
Apart from science,you need to stack up armor, a lot of armor.Powerful control deck with a lot of removals,anti-aggro and late-value, especially from Dr. Boom’s hero powers (this is the reason i put one pixie in).