Mulligans
General Mulligans
Keleseth you must always keep, you can take out Bloodsail Corsair but I recommend not. tar creeper and Kabal Courier you should usually keep.
To make the deck more budget, swap Lich King for shadow word horror and Ysera for pint-sized potion or twilight acolyte, this deck is currently still being tested and when I make it more budget I will post it.