Mulligans
General Mulligans
Generally you want to mulligan for cards that will either ramp you up or keep you alive during the early and mid stages of the game. Wild Growth is pretty much an always keep as well as Twig of the World Tree which help setup the combo.
Combo Mulligans
The entire combo relies on Twig of the World Tree. There are actually two combo decks smashed into one with this build. You can either save up spells and use Malygos to OTK your opponent which is optimally the better OTK but if you really want to flex your meme game you can setup the Splintergraft into Stonetusk Boar OTK. Simply play Splintergraft and Stonetusk for nine mana and end turn. Next turn you play that juicy 10/10 boar and break Twig so you can Faceless the beast twice and SMOrc to your heart's content.
Control Mulligans
Spreading Plague is a great card for keeping aggressive decks at bay while combining it with Branching Paths in the later stages can also create a nasty board of taunt minions. Branching paths allows for you to either draw or armor so you can dig deep for combo cards or keep your health total at a decent level. Harrison Jones is teched in for some weapon removal for nice card draw.
Don’t let your memes be dreams!