Retreat to Coralhelm + Llanowar Scout + Selesnya Sanctuary

Retreat to Coralhelm

Llanowar Scout

Selesnya Sanctuary

How it works

1. Activate Llanowar Scout by tapping it, putting Selesnya Sanctuary from your hand onto the battlefield.
2. When Selesnya Sanctuary enters the battlefield, it and Retreat to Coralhelm trigger.
3. Resolve the Selesnya Sanctuary trigger, returning itself from the battlefield to your hand.
4. Resolve the Retreat to Coralhelm trigger, untapping Llanowar Scout.
5. Repeat.