Necrotic Ooze + Devoted Druid + Morselhoarder

Necrotic Ooze

Devoted Druid

Morselhoarder

How it works

1. Place a -1/-1 counter on Necrotic Ooze with Devoted Druid's ability and remove it with Morselhoarder's ability to add one mana of any color.
2. Repeat

By leveraging Necrotic Ooze’s remarkable ability to absorb the activated powers of creatures in the graveyard, you transform a pile of parts into an unstoppable engine. You tap the Ooze for green mana using Devoted Druid's text, then place a -1/-1 counter upon it to untap it; normally, the Druid would eventually perish from these counters, but Morselhoarder steps in by letting you simply remove that -1/-1 counter to generate any color of mana instead. Because Morselhoarder's removal ability eats the exact counter that Devoted Druid just placed, the Ooze never accumulates a fatal load and can repeat the cycle endlessly. The result is an infinite reservoir of colored mana to fuel whatever devastating spell you choose to cast next.