Fertilid + Lotus Cobra + Spelunking + Thranduil's Company

Fertilid

Lotus Cobra

Spelunking

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 Spelunking.
2. When the basic land enters, Lotus Cobra and Thranduil's Company trigger.
3. Resolve the Lotus Cobra trigger, adding .
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. Repeat.

This loop turns Fertilid into a self-sustaining land-tutor engine by feeding its counter-removal cost directly back into itself. Every time Fertilid fetches a basic land, Spelunking ensures that land enters untapped so you can immediately tap it for mana while Lotus Cobra provides the green mana needed for the activation fee. Meanwhile, Thranduil's Company acts as the crucial engine upgrade, replacing the counters Fertilid removes with interest every time a land enters. With extra land drops enabled by Thranduil's Company—and Spelunking sweeping away any worries about tapped lands—you can easily strip your entire deck of basic lands in one fell swoop.