Extravagant Replication + Eternal Witness + Time Warp

Extravagant Replication

Eternal Witness

Time Warp

How it works

1. Cast Time Warp by paying its mana cost, causing you to take an extra turn after this one.
2. Move to your next turn.
3. At the beginning of your upkeep, Extravagant Replication triggers, creating a token copy of Eternal Witness.
4. When the Eternal Witness token enters the battlefield, it triggers, returning Time Warp from your graveyard to your hand.
5. Repeat.