Another way to defeat a solid deck like U/W Flash is to go under them. They may have the ability to control the skies and create destabilizing tempo plays, but not if they don’t have any good blocks for the bigger and more aggressive creatures on the ground.
One of the premier aggressive creatures to come out of Kaladesh is Voltaic Brawler. A 4/3 trampler for 2 mana is an absurd rate, but you do need to make sure there’s enough energy to feed this thing. If your opponents are going to play Spell Quellers, Reflector Mages, Spirits, and Gideon, Ally of Zendikar Knight tokens to block with, a 4/3 trampler that can come down on turn 2 should do a ton of damage.
Servant of the Conduit has demonstrated its power in aggressive shells as a way to accelerate, fix colors, and stockpile energy while still being a reasonable bear to attack with. Longtusk Cub is one of the best ways to utilize the creatures that provide incidental energy. You would much rather use the energy provided by Servant entering the battlefield, or even a Voltaic Brawler, to immediately pump the Cub. This will provide more energy and allow your deck to snowball in the right direction.
Bristling Hydra is the big payoff. This thing is tough to deal with, since the first spell or ability that targets it will end up fizzling. What you’re then left with is a 5/4 creature, up a card, and for a mere 4 mana. That rate is fantastic, and if you’re able to stockpile up some additional energy to protect the Hydra again, it should run away with the game.
Attune with Aether helps fix your mana and gives you free energy, and Harnessed Lightning’s will either killing something small and gain energy, or let you use excess energy to kill the biggest creature on the board.
This deck does a great job of utilizing the awesome planeswalkers that haven’t seen nearly the play we expected. Chandra, Torch of Defiance was hyped as being the next Jace, the Mind Sculptor. She has 4 great abilities, high loyalty, and all at only 4 mana. Chandra didn’t have the impact we anticipated largely due to the popularity and power level of cards like Smuggler’s Copter and Fleetwheel Cruiser, but she’s still a reasonable removal spell with incredible upside. Unopposed, Chandra threatens to ultimate and win the game rather quickly. Until that happens, it promises to kill creatures, draw cards, and deal incidental damage. All of these things are great in a R/G aggressive shell.
Nissa, Vital Force also attacks well, can ultimate the turn after you play it, or start returning key cards from your graveyard to your hand. Nissa creates a 5/5 creature the turn she comes down, a bit like Reality Smasher. Because she can be attacked by Vehicles and creatures with flying, she does have some weaknesses the Smasher doesn’t have, and she also doesn’t grant trample. If they don’t have an attack force in play, however, Nissa will take over and win the game on her own.
With solid cards in the early and late game, such as Tireless Tracker to generate value, Blossoming Defense to protect creatures and win combat, or Incendiary Flow to kill creatures or burn opponents out, R/G Aggro does a great job of utilizing the energy mechanic without needing to go all-in on Pummelers and pump spells.