Agatha of the Vile Cauldron + Fire Nation Archers + Thermopod

Agatha of the Vile Cauldron

Fire Nation Archers

Thermopod

How it works

1. Activate Fire Nation Archers by paying 1, dealing 2 damage to each opponent and creating a 2/2 Soldier creature token.
2. Activate Thermopod by sacrificing the Soldier, adding .
3. Repeat

This loop is all about engineering a massive cost reduction using Agatha of the Vile Cauldron, whose passive ability drops the price of creature activated abilities by an amount equal to her power. With Agatha's power pumped high enough, that discount reduces the activation cost of Fire Nation Archers' ability down to its hard floor of a single mana. You can then repeatedly pay that single {1} to blast your opponents and pump out 2/2 red Soldier creature tokens, which are immediately fed to Thermopod to generate the red mana needed to keep the cycle going.