This matchup is a race against a colorless-heavy Eldrazi ramp shell; White Orchid Phantom's land destruction on Eldrazi Temple, Cavern of Souls, Urza's Saga, or Boseiju is devastating since they have few basics to fetch back. Kaito, Bane of Nightmares gives another proactive threat with evasion and card advantage via Ninjutsu. Quantum Riddler is too slow against their explosive draws, and Prismatic Ending cannot hit their high-mana-value threats like Devourer of Destiny and Emrakul at all. Keep Thoughtseize and Solitude to strip/answer their key pieces before they combo off.

Against Izzet Prowess's low-to-the-ground aggro plan, High Noon is excellent, slowing their one-mana burn and cantrip barrage to one spell per turn. Consign to Memory can counter Cori-Steel Cutter's Flurry token trigger and stop noncreature colorless spells like Mishra's Bauble. Witch Enchanter's artifact/enchantment destruction is a weak use of a card against a deck with only a few artifacts, so it comes out for more impactful interaction. Solitude and Orcish Bowmasters remain critical to answer their early threats and punish cantrips.

In the mirror, White Orchid Phantom is a great value two-drop with flying/first strike that can destroy a shock land or other nonbasic, denying fixing. Mystical Dispute costs just {U} against their many blue spells like Quantum Riddler and Kaito, making it efficient interaction. Flickerwisp is redundant with your own blink package and less impactful when the opponent has answers like Fatal Push and Orcish Bowmasters ready. Keep your Thoughtseizes and removal suite intact since disrupting their Overlord of the Balemurk and Solitude is the priority.