Jeskai Black is already a 4-color deck loaded with powerful cards, so a new set added into the mix means that the most powerful cards will all be options for this Standard deck. It just so happens that many of the most powerful mythic rares in Oath of the Gatewatch are great fits for Jeskai Black.
Chandra, Flamecaller was my pick for best card in the set on Constructed Resources. It does so much on every board state—creating a powerful attack force when ahead, drawing a ton of cards when at parity, or wiping the board when behind. Chandra combines well with the already great removal in Jeskai Black to help ensure that you never have to use her -4, and when you actually do sweep creatures off the board, you aren’t facing down a 5-toughness creature.
Kalitas, Traitor of Ghet is a large body with a bigger effect. Jeskai Black can’t actually play Anafenza, the Foremost, but Kalitas is the kind of stretch to the mana base I can get behind. It has a large body with enough toughness to survive a Fiery Impulse, and enough power that lifelink is relevant against aggro, and shutting down Rally the Ancestors is a nice finish. Everything in between—namely the combination with cheap removal like Fiery Impulse and Roast to keep a chain of Zombies happening—is what makes Kalitas such a strong card.
Linvala, the Preserver is an interesting card, and I’m not sure yet how it will play out. Generating multiple flying bodies is great, gaining a bunch of life is great, and doing both is potentially game-ending. Linvala isn’t cheap to get on the board, and a 5/5 flying creature alone isn’t worth the investment. Assuming you will consistently be able to get one or both bonuses, as you should when you’re sideboarding Linvala in, you have a powerhouse.
Wandering Fumarole is one of the best manlands I’ve seen. It deals tons of damage, threatening to kill a Gideon, Ally of Zendikar if you can shoot down the token during an opponent’s end step, which is a real threat. This is also one of the very best ways to actually threaten a card like Ugin, the Spirit Dragon, which a land like Shambling Vent can’t do effectively.
The deck with lots of rares and shiny toys got a bunch of new ones to work with in Oath of the Gatewatch. I really love what Chandra can do in this deck and look forward to seeing her potential in Standard!