Fertilid + Nissa, Resurgent Animist + Archelos, Lagoon Mystic + Beorn's Hospitality

Fertilid

Nissa, Resurgent Animist

Archelos, Lagoon Mystic

Beorn's Hospitality

How it works

1. Activate Fertilid by paying 1 and removing a +1/+1 counter from it, causing you to search your library for a basic land card and put it on the battlefield untapped due to Archelos.
2. When the basic land enters, Nissa and Beorn's Hospitality trigger.
3. Resolve the Nissa trigger, adding .
4. Resolve the Beorn's Hospitality trigger, putting a +1/+1 counter on Fertilid.
5. Activate the basic land by tapping it, adding 1.
6. Repeat.

This elegant engine converts Fertilid's counter-removal into a self-sustaining loop by leveraging Archelos, Lagoon Mystic to ensure lands enter untapped so they can immediately tap for the mana needed to keep going. As those lands enter, Nissa, Resurgent Animist fuels the loop by generating color-fixing mana on each landfall trigger, while Beorn's Hospitality constantly replenishes Fertilid with the +1/+1 counters required to activate its search ability all over again.