So Innistrad spoilers of interest.
There's Flashback coming back as a mechanic, Decayed as a mechanic(creature with Decayed can't block, when it attacks sacrifice it at the end of turn seems to be for graveyard resurrection and zombies), Coven as a mechanic(Stuff happens if you control three or more creatures with different power) and Day and Night cycles and transforming cards, which I'm not super sure about.
Like, if I have
Tavern Ruffian(Daybound face, Nightbound back) does it transform back and forth as Day turns into Night and vice versa or do I need some other specific card to transform them?
Anyway, there's also some curses and a cycle of allied color dual lands that come into play tapped unless you control two or more lands.
A particularly interesting, lorewise, card that's turned up?
Liesa, Forgotten Archangel. 2WWB Legendary Creature Angel, 4/5 Flying Lifelink. If a nontoken creature you control would die, return it to its owner's hand at the next end step. If an opponent's creature would die, exile it instead.
IIRC, didn't Avacyn kill her for consorting with demons? Liesa flying around is definitely an interesting turn of events.