Consign to Memory is excellent against Eldrazi Tron's heavily colorless deck, countering colorless spells like Thought-Knot Seer, Devourer of Destiny, Mind Stone, and Kozilek's Command outright. It can also counter triggered abilities such as Thought-Knot Seer's enter trigger or Devourer of Destiny's cast trigger, and replicate lets us hit multiple threats or abilities in one cast. Spell Snare only hits mana-value-2 spells and Spell Pierce is easy for their mana-rich deck to pay for, so both are much weaker here. Keep Solitude and our removal to answer Thought-Knot Seer and Devourer of Destiny once they land.