Retreat to Coralhelm + Scaled Herbalist + Orzhov Basilica

Retreat to Coralhelm

Scaled Herbalist

Orzhov Basilica

How it works

1. Activate Scaled Herbalist by tapping it, putting Orzhov Basilica from your hand onto the battlefield.
2. When Orzhov Basilica enters the battlefield, it and Retreat to Coralhelm trigger.
3. Resolve the Orzhov Basilica trigger, returning itself from the battlefield to your hand.
4. Resolve the Retreat to Coralhelm trigger, untapping Scaled Herbalist.
5. Repeat.