Eldrazi Tron assembles enormous mana via Tron lands and Eldrazi Temple to deploy Karn, the Great Creator, Thought-Knot Seer, and eventually Emrakul or Ulamog — Karn in particular is their most dangerous card as it tutors silver bullets and locks you out of artifacts. Counterspell and Mystical Dispute are your core interaction since most of their threats and Karn require hard counters, and Mystical Dispute's alternate cost is often active given their colorless-heavy deck still runs some blue via Ugin. Consign to Memory handles Karn's Wish targets and any artifact threats they deploy, and Force of Negation is free interaction against their key spells. Your creature removal is nearly useless here since they run very few creatures, so sweepers come out entirely. Orim's Chant is situationally powerful to stop a Karn activation or large Eldrazi attack, buying time to find your counterspells.