Mulligans
General Mulligans
See aggro and control.
Aggro Mulligans
Never shuffle first idol. Jade Blossom, crypt lord and spreading plague can be keeped if you have innervate.
Control Mulligans
Vs control you want to keep ramp and card draw mostly, possibly keep Malfurion vs the slower decks for the insane hero power and ok for cost Chose One ability.
Even though Skulking Geist might put and end to Jade druid going infinite, most decks should not run it, and also Jade druid should be more then strong enough to still be Tier 1. Just remember; never shuffle first Jade Idol 😉
Malfurion the Pestilent replaces Acient of war, you are getting 2/10 (efficiently 1/10) of taunt stats instead of 5/10, but you are also getting 5 armor and an insane hero power upgrade.
Ultimate Infestation replaces Gadgetzan Auctioneer for a slower but stabler draw that also provides armor to help vs burst and a 5 damage removal/burst.
Spreading Plague, Crypt Lord and Druid of the Swarm are all delay defence for you to get to your crazy mid to lategame.