Collector Ouphe doesn't stop Aluren itself (an enchantment, not an artifact), but it shuts off Lotus Petal. City of Traitors and Ancient Tomb are lands, so their mana is unaffected. It's a modest hit on their acceleration, and it doubles as a real clock. Force of Vigor is premium removal for Aluren and Omniscience (it can also hit Lotus Petal), and it can be cast for free by exiling a green card from hand on the opponent's turn to blow up their engine. Endurance is a flash 3/4 reach body that blocks well and applies a clock. Fatal Push and Snuff Out are mostly weak against their plan: Atraxa, Grand Unifier has mana value 7 and dodges Fatal Push, and both Atraxa and Acererak the Archlich are black, so Snuff Out can't target them. That makes them the first cuts alongside the narrower utility lands.