Mulligans
General Mulligans
Town crier is indisputably the best one drop, if not card, in the deck. It draws you a threat and is a resilient presence in the early game. there is literally no situation where you should mulligan this away.
Dr. Boom, Mad genius is everything this deck wants to be doing, and playing it on seven is what you want to be doing every game. mull if the game could end before turn 5.
Crowd roaster and unseen Saboteur are both tech cards and are not keep able in most match ups by any metric of the word.
Aggro Mulligans
eternium rover both removes problematic threats in the early game, as well as gains you as much as 6 armor, which helps cushion your health total in the early game.
Hench-clan Hogsteed is one of the best cards in this matchup as it is an early game threat that doubles as a removal spell that makes a 1/1.
Warpath and Dragonmaw are obvious all-stars in this sort of match-up. having cards that can single handedly win you the game should not be underestimated.
Combo Mulligans
Unseen Saboteur breaks their combo, while emberscale drake makes it harder to otk you.
Control Mulligans
You should keep cards that will generate at least 2 cards worth of value, as this whole match up relies on who can out grind the other player.