Meltdown blows up their artifacts like Urza's Saga tokens and Vexing Bauble, while Pyroclasm sweeps their small Basking Broodscale/Glaring Fleshraker/Eldrazi Spawn tokens for 2 damage each. Dauthi Voidwalker's shadow evasion races well since they have no shadow blockers, and it can tap and sacrifice itself to play an exiled card. Quantum Riddler is too slow against their proactive ramp plan and Sink into Stupor doesn't answer a resolved Emrakul or Devourer of Destiny. Keep the graveyard-recursion engine (Persist, Unearth, Archon of Cruelty) intact since it out-races their grindy value plan.

Consign to Memory counters colorless spells and triggered abilities, but their deck is mostly Dragon's Rage Channeler/Monastery Swiftspear/burn spells with few colorless targets, so it's really here as a Mishra's Bauble answer rather than a full counter suite. Spell Snare is excellent, hitting Slickshot Show-Off, Expressive Iteration, and Cori-Steel Cutter (all MV2). Quantum Riddler is too slow and dies to their removal before it does much, and Thought Scour doesn't affect the race. Keep Fatal Push and Psychic Frog as your primary interaction against their small creatures and clock.

Consign to Memory counters their Phelia/Flickerwisp blink triggers and Solitude/Overlord of the Balemurk enter-the-battlefield triggers, disrupting their entire value engine, while also stopping colorless spells if any show up. Mystical Dispute is cheap interaction against their blue spells like Kaito or their own countermagic, and can also counter anything for {2}{U} unless they pay {3} when not targeting blue. Quantum Riddler is a poor blocker against their evasive threats and doesn't interact, so it comes out in favor of proactive disruption. Your Thoughtseize and Fatal Push remain crucial to strip their key blink pieces before they combo off.