Devoted Druid + Necklace of Girion + Cloudstone Curio

Devoted Druid

Necklace of Girion

Cloudstone Curio

How it works

1. Activate Devoted Druid's first ability by tapping it, adding .
2. Cast the creature castable for in your hand by paying its mana cost
3. Necklace of Girion triggers, putting a +1/+1 counter on Devoted Druid.
4. Resolve the creature spell. When the creature enters, Cloudstone Curio triggers, returning the other creature that's castable for from the battlefield to your hand.
5. Activate Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
6. Repeat.

This clever loop relies on Devoted Druid generating green mana while Cloudstone Curio handles the bouncing, letting you recast a cheap green creature endlessly. As you repeatedly cast that green spell, Necklace of Girion's triggered ability steps in to place +1/+1 counters on Devoted Druid, effortlessly neutralizing the -1/-1 counters the druid accumulates when untapping itself.