Really interesting answers, guys!
I think there are at least 9 or 10 cards, you could make an argument for as a firstpick here.
I'm surprised that noone has mentioned Earthquake, though, that's a really good sweeper, that can be okay as a fireball variant in an aggro deck.
I’m torn between Wrecking Ball and Wayfinder. If your list is light on premium removal, then I’d probably take the Ball, otherwise I’d go with Wayfinder to stay open.