Underworld Breach + Malevolent Rumble + Concordant Crossroads + Jaheira, Friend of the Forest

Underworld Breach

Malevolent Rumble

Concordant Crossroads

Jaheira, Friend of the Forest

How it works

1. Cast Malevolent Rumble for its escape cost by paying 1 and exiling three other cards from your graveyard, causing you to mill at least three cards and create a 0/1 Eldrazi Spawn creature token.
2. Activate the Eldrazi Spawn by tapping it, adding .
3. Activate the Eldrazi Spawn by sacrificing it, adding C.
4. Repeat.

This loop turns the graveyard into an endless engine by using Underworld Breach to cast Malevolent Rumble over and over again from your graveyard for its escape cost. As Malevolent Rumble fills your graveyard and creates Eldrazi Spawn tokens, Concordant Crossroads makes sure those tokens can tap immediately without waiting for summoning sickness. Meanwhile, Jaheira, Friend of the Forest turns every single one of those tokens into an active mana source, providing the green mana needed to continuously recast the spell while leaving the token's sacrifice ability ready to supplement your colorless mana needs.