Careful Cultivation + Umbral Mantle + Heartstone

Careful Cultivation

Umbral Mantle

Heartstone

How it works

1. Activate the creature with Careful Cultivation and Umbral Mantle attached by tapping it, adding .
2. Activate the creature by paying 2 and untapping it, causing it to get +2/+2 until end of turn.
3. Repeat.

This brew turns any unassuming creature into an absolute engine by layering a mana-producer with a massive stat-buffing untap loop. By enchanting your chosen creature with Careful Cultivation, you grant it the tap ability to generate double green mana, while equipping it with Umbral Mantle allows it to untap itself. Normally, Umbral Mantle's untap ability costs three mana, but with Heartstone on the battlefield reducing creature activated abilities by {1}, that cost drops to just two—leaving you with a net profit of {G}{G} every single cycle. You can repeat this process as many times as you like to pump the creature to infinitely large proportions while flooding your mana pool.