Time Sieve + Encroaching Mycosynth + Helm of the Host + Izoni, Thousand-Eyed

Time Sieve

Encroaching Mycosynth

Helm of the Host

Izoni, Thousand-Eyed

How it works

1. At the beginning of your combat phase, Helm of the Host triggers, creating a nonlegendary token copy of Izoni with haste.
2. When the Izoni token enters the battlefield, it triggers, creating a number of 1/1 Insect creature tokens equal to the number of creature cards in your graveyard.
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 engine transforms the combat step into a relentless loop of extra turns by turning your entire board into artifact fuel. The setup relies on Encroaching Mycosynth to make all your nonland permanents and creatures into artifacts, which covertly feeds Time Sieve's activation cost with any creatures you have lying around. Each combat, Helm of the Host creates a fresh, nonlegendary copy of Izoni, Thousand-Eyed, whose entrance triggers to flood the battlefield with a swarm of Insect tokens. You then simply tap Time Sieve, sacrifice five of those newly minted bug tokens, and secure an endless sequence of extra turns to bury your opponents.