Thalia puts a halt on decks like storm combo all by itself, and its a needed feature to survive fast combo formats like Legacy and Vintage
This is where youre given the ability to accelerate your mana, but only to help you keep up with the players that are furthest ahead
Your best bet is probably trying to pick up some Blinding Beams, which is still as good a finisher now as it was back in its heyday
Diamond Weapon Commanders with innate mana reduction are always handy because cost reduction reduces command tax, so its easy to cast Diamond Weapon multiple times in a game
And with just one black mana required, it's easy to splash into other colors, too
VIVI ORNITIER Vivi Ornitier is the most infamous Commander in the set, and many folks are already trying to break him wide open