This Gruul deck combos off with Basking Broodscale and Kozilek's Command loops fueled by artifact lands and Urza's Saga, making Force of Vigor and Brotherhood's End premium answers that can strip their engine pieces or blow up a Saga before it makes a Construct. Sink into Stupor is too slow against their combo-oriented plan, so it's cut for proactive disruption. Endurance is valuable both as a cheap blocker against Glaring Fleshraker and to exile their graveyard if they're looping Devourer of Destiny or Malevolent Rumble triggers. Race with Living End while using your artifact hate to disrupt their engine rather than trying to grind since their late game outclasses yours.

Izzet Prowess is an extremely fast, low-curve aggro-tempo deck built around Monastery Swiftspear and Dragon's Rage Channeler, so Force of Negation pitching your hand is far too costly against a clock this quick — you need every card to stabilize or race. Mystical Dispute is live against their blue cantrips like Preordain and Expressive Iteration, and Brotherhood's End sweeps their small creatures if you fall behind on board. Endurance is fantastic both as a zero-mana blocker to stem the bleeding and to hate out their graveyard against Dragon's Rage Channeler delirium. Try to Living End into Endurance/Subtlety-heavy configurations that stabilize the board rather than durdling with slower disruption.

Boros Energy is a fast, low-to-the-ground aggro-tempo deck full of one- and two-mana threats like Ragavan, Nimble Pilferer and Ocelot Pride, so Force of Negation is often too slow and too narrow against their curve of cheap permanents. Mystical Dispute comes in as a flexible counter that's excellent against their Blood Moon and any blue hate they bring in, while Force of Vigor blows up Ocelot Pride tokens' enablers, Guide of Souls, and any artifacts/enchantments like Static Prison or The Legend of Roku. Prioritize resolving Living End on curve since their removal is mostly burn aimed at your face and creatures, not counterspells. Keep Endurance in to fight through their graveyard hate and to snipe Ragavan.