Izzet Tempo vs Jeskai Artifacts

Null Rod is devastating against Jeskai Artifacts since it turns off Goblin Welder, Goblin Engineer's activated ability, Emry's activated ability, and Mox Opal's mana ability, crippling their entire engine. Meltdown can blow out their critical mana rocks like Mox Opal, Lotus Petal, and Chromatic Star for a low X. Unholy Heat struggles to find good targets against their mostly small or artifact-shielded creatures, so it's trimmed. Keep Wasteland to attack Urza's Saga before it can tutor up their key artifacts, as denying that land is often the single best play available.