Earthcraft + Intruder Alarm + Deeproot Pilgrimage

Earthcraft

Intruder Alarm

Deeproot Pilgrimage

How it works

1. Activate Earthcraft by tapping a nontoken Merfolk you control, targeting any basic land.
2. Deeproot Pilgrimage triggers, creating a 1/1 Merfolk creature token.
3. When the Merfolk enters the battlefield, Intruder Alarm triggers, untapping all creatures.
4. Resolve the Earthcraft ability, untapping the basic land.
5. If you controlled the basic land, you may activate it by tapping it, adding 1.
6. Repeat.

This loop turns your Merfolk into mana-producing engines by combining Earthcraft with Deeproot Pilgrimage, which triggers to manufacture a fresh 1/1 token every time you tap a nontoken Merfolk for Earthcraft's land-untapping cost. Each token entering the battlefield immediately wakes up the entire board thanks to Intruder Alarm's global untap trigger, leaving your creatures and basic land freshly untaped and ready to repeat the cycle. This creates an endless loop of creature entries, tokens, and mana generation that you can ride straight to victory in Commander, Oathbreaker, or Vintage.