Fertilid + Tireless Provisioner + Horizon Explorer + Thranduil's Company

Fertilid

Tireless Provisioner

Horizon Explorer

Thranduil's Company

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 Horizon Explorer.
2. When the basic land enters, Tireless Provisioner and Thranduil's Company trigger.
3. Resolve the Tireless Provisioner trigger, creating a Treasure token
4. Resolve the Thranduil's Company trigger, putting two +1/+1 counters on Fertilid.
5. Activate the basic land by tapping it, adding 1.
6. Activate the Treasure by tapping and sacrificing it, adding .
7. Repeat.

This clever loop transforms Fertilid's counter-removal cost into a self-sustaining engine by cycling basic lands straight from your library onto the battlefield. Horizon Explorer ensures those lands enter untapped so they can immediately tap for mana, while Tireless Provisioner supplies the necessary green mana by spinning off Treasure tokens whenever a land drops. Meanwhile, Thranduil's Company provides the crucial engine fuel by continuously replacing the +1/+1 counters Fertilid spends, keeping the loop powered indefinitely.