Mulligans
General Mulligans
Generally you want to keep things that can cheat out your minions, though there are exceptions. Barnes is always 100% a must-keep regardless
Aggro Mulligans
Situational, always keep Barnes but the rest depends on the matchup. These are just a few examples of stuff that could be good to keep
Midrange Mulligans
Pretty much the only midrange deck being played right now is Even Shaman. Pain is great vs all their early drops, Death is great for 4 mana 7/7, 0 mana 5/5 taunt and Sea Giant, Lightbomb is great for when they go wide with big stuff
Combo Mulligans
The only combo decks out there right now are Aligner and Tog Druid, and both are a disaster for you. Basically just pray to cheat big stuff out and race them before they get to their combo
Vs Tog, keep the Spellstone as you really don't want them to steal it
Control Mulligans
Hard mulligan for ways to cheat minions out, keep res tools if you've met that prerequisite
Peaked at L14 (NA – SMOrc#11429). Still optimizing but current build feels pretty strong