Mulligans
General Mulligans
Reckless experimenter turns your draw deathrattles into 0 mana cycle, your eggs into bags of stats, and your obsidian statues into 3 mana 4/8's that add a deadly shot to your hand that you have to cast that turn. Twilight call helps you finish your quest, too.
Aggro Mulligans
Finish the quest as soon as possible while cycling through the deck. Run them out of resources and psychic scream them when they go wide, and hold your two reno jacksons for as long as you need.
Control Mulligans
Use voodoo doll as an assassinate, and summon a ton of eggs and crashers to bring out statues and cube the statues and make more statues.
Use reckless experimenter into your draw deathrattles to cycle for a ton of draws. Use 3 mana Coffin Crashers to bring out Obsidian Statues and 2 mana cube those to destroy enemy minions and bring out even more obsidian statues. Voodoo Doll is a 0 mana destroy an enemy minion at the end of your turn, which is absolutely insane, Devilsaur egg is a 0 mana 5/5 at the end of your turn. But the star aligner combo is also in here for the memes; turn 5 reckless experimenter, turn 6 mechanical whelp into cube, which summons you two mechanical whelps and a 7/7, Turn 7 trade one or two of the 2/2 mechanical whelps and play Star Aligner and now you’ve dealt 7 damage to all enemies so you’re way ahead. This is also a dream scenario though. With a freshly summoned Obsidian Statue from the previous turn and reckless experimenter, you can play umbra into cube on the statue to flood your board with four Obsidian Statues and kill 5 enemy minions (1 from the cube battlecry, 2 from the first cube deathrattle’s summoning, and 2 from the death of the cube). It’s an insane deck if Reckless Experimenter can survive a turn or two.