Mulligans
General Mulligans
Generally, you want to get your 1 drops and you can always look for Phase Stalker on the coin and Scavenger's Ingenuity as well.
Aggro Mulligans
Against Aggro deck, you want adorable infestation to buff your minions so they can contest the board and hit harder in your opponent's face. Aggro mirrors are either games that depend heavily on knowing when to go face and when to remove board threats. Initiate is board presence that an aggro deck has to deal with and Dwarven Sharpshooter allows for your hero power to act as a clearing agent to help keeps minions alive so you want them on board as fast as possible.