BO1 demon
Probably the most fun deck to play in my opinion. Suprisingly, though i think it's because of the auto shuffler in BO1, this deck is extremely consistent for a highlander deck with wins from turn 4-7 not being uncommon.
Tips and tricks:
Always play thoracle first while having full control and then play tainted pact as a response to the trigger. This is because if you have two tainted pacts in your hand you can get a countered thoracle but mainly it's because if you play tainted pact first to mill yourself completely and they counter thoracle then its over for you, however if they either counter thoracle that you played first or dont its a win win for you technically because if they counter thoracle then you dont have to play your tainted pact and if they dont then they have to counter your tainted pact or lose so you end up either winning or having a thassa's oracle on the board and a full library.
A lot of people don't know this combo so they don't really know what to counter or discard which is an advantage in a way.
When building the deck focus on redundancy and cards like lorien revealed, sink into stupor and other mdfcs are really good because they act as two cards at once which is really important in a singleton deck.