Mulligans
General Mulligans
These are your bread and butter to start with, different cards are better depending on what deck you are facing.
Play Hagatha the Witch, generate spells.
Play Archivist Elysiana, generate more spells with Hagatha the Witch and add 10 to your deck once you start fatigue.
Play Shudderwock, add 10 more cards to your deck by repeating Archivist Elysiana, then generate more spells from Hagatha the Witch.
Essentially a deck of 50 cards which generate infinitely with Hagatha the Witch.