Galadriel of Lothlórien + Dryad Arbor + Retreat to Coralhelm + Mortuary + Phyrexian Altar

Galadriel of Lothlórien

Dryad Arbor

Retreat to Coralhelm

Mortuary

Phyrexian Altar

How it works

1. Play Dryad Arbor.
2. When Dryad Arbor enters the battlefield, Retreat to Coralhelm triggers.
3. Holding priority, activate Phyrexian Altar by sacrificing Dryad Arbor, adding one mana of any color.
4. When Dryad Arbor dies, Mortuary triggers, putting Dryad Arbor on top of your library from your graveyard.
5. Resolve the Retreat to Coralhelm trigger from step 2, causing you to scry 1, ensuring to leave Dryad Arbor on top of your library.
6. Galadriel's second ability triggers, causing you to reveal Dryad Arbor from the top of your library, and put it onto the battlefield tapped.
7. Repeat from step 2.