Sprout Swarm + Pitiless Plunderer + Phyrexian Altar + Doubling Season

Sprout Swarm

Pitiless Plunderer

Phyrexian Altar

Doubling Season

How it works

1. Cast Sprout Swarm with buyback by paying 4, creating two 1/1 Saproling creature tokens.
2. Activate Phyrexian Altar twice by sacrificing the Saprolings, adding 1.
3. When the Saprolings die, Pitiless Plunderer triggers twice, creating four Treasure artifact tokens.
4. Activate three Treasures by tapping and sacrificing them, adding 3.
5. Repeat.
6. Once you have infinite Treasure tokens and colored mana, you may forego sacrificing the Saproling tokens.

This delightful loop turns the humble Sprout Swarm into an engine for infinite resources by leveraging a cascading web of token generation and sacrifice. When you cast Sprout Swarm with its buyback cost, Doubling Season steps in to double your creature output, immediately yielding two Saproling tokens instead of one. As those Saprolings meet their end at the Phyrexian Altar, Pitiless Plunderer witnesses the deaths and triggers to churn out an excess of Treasure tokens, which can then be sacrificed to feed both the mana needs of the Altar and the ongoing buyback costs.