Fertilid + Crystalline Crawler + Avenger of Zendikar + Ancient Greenwarden + Arcane Adaptation

Fertilid

Crystalline Crawler

Avenger of Zendikar

Ancient Greenwarden

Arcane Adaptation

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 onto the battlefield tapped.
2. When the land enters the battlefield, Avenger of Zendikar's second ability triggers twice, putting two +1/+1 counters on each creature you control.
3. Activate Crystalline Crawler's first ability twice by removing two +1/+1 counters from it, adding 1.
4. Repeat.

This clever loop transforms simple land-fetching into an overwhelming board state by exploiting creature type manipulation and counter economy. With Arcane Adaptation naming "Elemental" (or another appropriate type), your Fertilid and Crystalline Crawler count as Plants alongside the tokens created by Avenger of Zendikar, allowing them to benefit directly from landfall growth. Meanwhile, Ancient Greenwarden doubles those landfall triggers so that every basic land fetched pumps your entire team with pairs of +1/+1 counters. You can then strip those newly minted counters from Crystalline Crawler to generate the exact green and generic mana needed to pay for Fertilid's ability, sustaining a self-feeding loop that dumps every single basic land from your library straight onto the battlefield.