Time Vault, and Tezzeret the Seeker

Prerequisites

• Time Vault on the battlefield
• Tezzeret the Seeker on the battlefield

Steps

1. Activate Tezzeret the Seeker's first loyalty ability by putting a loyalty counter on it, untap Time Vault
2. Activate Time Vault by tapping it, causing you to take an extra turn after this one
3. Repeat each turn

Results

• Infinite turns