Fire Magic at the Fira tier for {2} deals 2 damage to each creature, sweeping their army of 1-toughness tokens (Cat Warriors, Warrior tokens) and hitting Guide of Souls and Ocelot Pride. Meltdown answers Goblin Bombardment for a cheap cost and can scale up against nothing else major but is still a solid one-for-one artifact answer if needed. We're already well-suited against their planeswalkers with Lightning Bolt and Unholy Heat, so we make only small adjustments, trimming a Spell Pierce since they have plenty of proactive threats that don't care about a tax effect and cutting a Consign to Memory copy since they have few colorless spells or key triggered abilities to target.