Mono-Green Eldrazi ramps through Fanatic of Rhonas into Emrakul, the Promised End and Ulamog, the Ceaseless Hunger. Thoughtseize taken on an early turn can strip a key ramp piece or top-end threat before it comes down. Feed the Swarm is excellent removal here, killing Fanatic of Rhonas to slow their mana or Fight Rigging before it enables their big spells. Since this is a disruption race rather than a combat-trick race, Mutagenic Growth and Violent Urge come out.

This ramp deck leans on cheap mana (Eldrazi Spawn tokens, Ancient Stirrings hits) to power out Devourer of Destiny and Emrakul, the Promised End. Thoughtseize taken early strips a key piece like Malevolent Rumble or a big Eldrazi threat before it can take over the game. Meltdown for X=0 or X=1 cleans up Urza's Saga's Construct tokens and other cheap artifacts that enable their mana. Feed the Swarm can pick off Basking Broodscale or Devourer of Destiny once it resolves, though removing Devourer of Destiny costs 7 life. Mutagenic Growth and Violent Urge are combat-focused cards that matter less against a deck trying to go over the top of you, so they make room.

This is essentially a mirror match, so the deck that generates more value off each card tends to win. Dreadhorde Arcanist lets you re-cast a cheap Lightning Bolt or Lava Dart from the graveyard on attack, generating extra reach and card advantage the opposing list can't match. Thoughtseize taken proactively can strip their best spell (Expressive Iteration or a removal spell) before it can swing the race in their favor. Mutagenic Growth and Violent Urge are marginal combat tricks in a matchup decided more by resource efficiency than combat math, so they're cut for the extra bodies and disruption.