Choose a nonland card from each of those hands
#6: Red Elemental Blast/Pyroblast Speaking of the best sideboard cards of all-time, Red Elemental Blast and its nearly identical analog, Pyroblast, are extremely high on the all-time list, thanks to whole Counterspell + Maelstrom Pulse for one-mana thing, and in a color that doesnt get access to such things but greatly appreciates them
You hear this
The counter adding plays into proliferate and leaders in Simic that care about counters
Unfortunately, Ruinous Ultimatum is also wildly expensive, costing two red, three white, and two black
With both Kaladesh and Ixalan in Standard, it would be the right time for it, if there ever was one, but it hasnt happened yet, so I guess the theme doesnt have much to offer for cnostructed, unless they really want to push it, which I doubt theyll do