Time Sieve + Encroaching Mycosynth + Helm of the Host + Evangel of Heliod

Time Sieve

Encroaching Mycosynth

Helm of the Host

Evangel of Heliod

How it works

1. At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Evangel of Heliod with haste.
2. When the Evangel of Heliod token enters the battlefield, it triggers, creating a number of 1/1 Soldier creature tokens equal to your devotion to white.
3. Activate Time Sieve by tapping it and sacrificing five creature tokens, causing you to take an extra turn after this one.
4. Repeat each turn.

This loop relies on Encroaching Mycosynth to fundamentally rewrite the battlefield, turning all your nonland permanents into artifacts so they can fuel Time Sieve's sacrifice cost. Every combat step, Helm of the Host creates a fresh copy of Evangel of Heliod, whose entry ability immediately floods your board with enough Soldier tokens to pay Time Sieve's five-artifact toll. Because Time Sieve rewards you with an extra turn every single cycle, you get to continuously repeat this combat-and-sacrifice routine until you've locked down the game with infinite turns.