Tawnos, Solemn Survivor + Great Oak Guardian + Ashnod's Altar

Tawnos, Solemn Survivor

Great Oak Guardian

Ashnod's Altar

How it works

1. Activate Tawnos's second ability by paying 1, tapping it and sacrificing two artifact tokens, exiling Great Oak Guardian from your graveyard and creating a token copy of it that is an artifact in addition to its other types.
2. When the Great Oak Guardian token enters, it triggers, untapping all creatures you control and giving them +2/+2 until end of turn.
3. Activate Tawnos's first ability by paying 2 and tapping it, creating a copy of the Great Oak Guardian token and causing you to mill two cards.
4. When the Great Oak Guardian token enters, it triggers, untapping all creatures you control and giving them +2/+2 until end of turn.
5. Activate Ashnod's Altar by sacrificing a Great Oak Guardian token, adding CC.
6. Repeat from step 3.

This loop relies on Tawnos, Solemn Survivor using its secondary ability to exile Great Oak Guardian from your graveyard, producing an artifact copy of it that immediately triggers to untap your board and pump your team. Because that new token is an artifact, Tawnos's first ability can then target it to spin out a continuous stream of fresh Great Oak Guardian copies while milling your deck. Finally, Ashnod's Altar provides a crucial outlet by letting you sacrifice those looping tokens for colorlress mana, funding the {2} activation cost needed to keep the entire engine running indefinitely.