Mulligans
General Mulligans
Trap, Midirection, and Kill Command are generally cards you always wanna keep, they keep the board in line, and give you upper hand against their minions
Aggro Mulligans
Against Aggro, getting your guys out first is what is important, and if you can either wipe their board with the sheep, or gain quick damage with Hounds both are favorable. Alpha and Hyena are also good with synergy between the previous two, as they either get stronger with your beasts deaths, or give them a good push of damage too
Control Mulligans
Against Control you have to get as much damage as fast as possible. Highmane makes your opponent have to get rid of it, but with an advantage being given to you, and sand worm is an absolute monster at getting rid of your opponent's big guys. Abusive Seagent and Glaivezooka help these guys out to some extent as well.
Lastly, Call of the Wild is probably the best card in the deck, because it cripples a control player by giving them so much to have to deal with, and fast. The Only thing I would watch out for when play Call is Flamestrike and Brawl. Other than that, youre always gona wanna play this when you can.
This is a wild deck I adapted from a previous deck I used. It utilizes some control aspects while stacking a bunch of damage