Thopter Foundry + Time Sieve + Sword of the Meek

Thopter Foundry
Time Sieve
Sword of the Meek

Requires
All permanents on the battlefield. 5 available each turn.
Steps
  1. Activate Thopter Foundry by paying 1 and sacrificing Sword of the Meek, creating a 1/1 Thopter creature token and gaining 1 life
  2. The Thopter token enters the battlefield, triggering Sword of the Meek, returning it to the battlefield and attaching it to the Thopter token
  3. Repeat until you have 5 Thopters tokens
  4. Activate Time Sieve by tapping it and sacrificing 5 Thopter tokens, taking an extra turn after this one
  5. Move to your next turn
  6. Repeat
Results
Infinite turns.