Persist is a very sweet ability thats often looked down on because design teams avoid mixing mechanics that use +1/+1 and -1/-1 counters to minimize confusion, and mechanics that feature +1/+1 counters tend to be very popular
Typically the Nightbound side of the card is more powerful, and with this new mechanic, once it is nighttime Werewolves will enter the battlefield on their back Nightbound side
This deck took the format by storm through its fast paced gameplay, that got even faster due to the convoke ability (you can pay mana cost by tapping creature cards) that many of the decks most powerful cards featured
As a note at time of writing, the set is still being spoiled so there may be legends I miss, and obligatory spoiler warning
Izzet (red/blue) focuses on Rooms, which will reward your eerie synergies despite being off-color, while Dimir (blue/black) uses the same eerie synergies for a more control-based strategy