Winterspell is now available to buy at most major retailers, but I'd recommend at least picking up the Booster Display Pack for $144 at Amazon to really get you started with the new set
While these metrics are a solid foundation for in-print Standard-legal sets, what about if you move towards Pioneer, Modern, or Legacy
It's basically Mana Confluence, and in many scenarios, it's even better since you can generate colorless mana without pain
2 Embercleave Part combat trick, part Equipment, Embercleave is a classic game-ending win condition for aggro decks, provided you can get enough creatures on the board to bring that cost right down
Rilsa is all about finishing the dungeon, and if you do, she has deadly rewards for your creatures
It resolves (so long as the opponent doesnt counter it)