Time Sieve + Encroaching Mycosynth + Kiki-Jiki, Mirror Breaker + Abhorrent Overlord

Time Sieve

Encroaching Mycosynth

Kiki-Jiki, Mirror Breaker

Abhorrent Overlord

How it works

1. Activate Kiki-Jiki by tapping it, creating a token copy of Abhorrent Overlord with haste.
2. When the Abhorrent Overlord token enters the battlefield, it triggers, creating at least four 1/1 Harpy creature tokens.
3. Activate Time Sieve by tapping it, sacrificing the Abhorrent Overlord token and the Harpy tokens, causing you to take an extra turn after this one.
4. Repeat each turn.

This ingenious loop turns your entire board into an artifact-generating engine, anchored entirely by Encroaching Mycosynth turning every nonland permanent you control into an artifact. With that global transformation active, Kiki-Jiki, Mirror Breaker can repeatedly churn out temporary copies of Abhorrent Overlord, which floods your board with flying Harpy tokens thanks to your overwhelming devotion to black. You then feed those Harpies and the Abhorrent Overlord token directly into Time Sieve's sacrifice requirement to buy yourself an extra turn. Because Encroaching Mycosynth ensures everything you need is constantly primed as an artifact, you can simply repeat this process every turn to lock down the game with infinite extra turns.