Retreat to Coralhelm + Skyshroud Ranger + Azorius Chancery

Retreat to Coralhelm

Skyshroud Ranger

Azorius Chancery

How it works

1. Activate Skyshroud Ranger by tapping it, putting Azorius Chancery from your hand onto the battlefield.
2. When Azorius Chancery enters the battlefield, it and Retreat to Coralhelm trigger.
3. Resolve the Azorius Chancery trigger, returning itself from the battlefield to your hand.
4. Resolve the Retreat to Coralhelm trigger, untapping Skyshroud Ranger.
5. Repeat.