Selesnya Landfall's creature payoffs like Mightform Harmonizer and Icetill Explorer (and Dyadrine when X is 2 or more) all have mana value 4 or greater, so Disdainful Stroke counters them. It can't hit Earthbender Ascension or Mossborn Hydra (mana value 3) or lands like Ba Sing Se, so don't count on it for those. Thor, God of Thunder is a big flying threat: every noncreature spell we cast makes it deal damage equal to that spell's mana value to any target, which picks off Llanowar Elves and Sazh's Chocobo, though Erode can answer it. Shoot the Sheriff stays in, since none of their creatures are outlaw types and it kills any of them. Duress has few impactful noncreature targets to take in a creature-and-land-dense deck, and Flashback is too low-impact here. Keep removal in to answer Mightform Harmonizer and Mossborn Hydra before landfall snowballs.