Yedora, Grave Gardener + Ambush Commander + Yahenni, Undying Partisan

Yedora, Grave Gardener

Ambush Commander

Yahenni, Undying Partisan

How it works

1. Activate Yahenni by sacrificing a nontoken Forest, which is a creature due to Ambush Commander.
2. When the Forest dies, Yedora triggers, returning the Forest from your graveyard to the battlefield face down as a Forest land.
3. Resolve the Yahenni ability.
4. Repeat.

This clever looping engine relies on Ambush Commander's static ability to turn every single Forest you control into a 1/1 green Elf creature, seamlessly bridging the gap between your land base and your graveyard. Once those lands are creatures, Yahenni, Undying Partisan can repeatedly sacrifice them to its own activation, which also conveniently grants Yahenni indestructible to protect itself. Each time one of those creature-lands hits the graveyard, Yedora, Grave Gardener steps in with its replacement-style trigger to rescue the card, bringing it right back to the battlefield face down as a fresh Forest land. Because that returned land is immediately re-animated as a creature by Ambush Commander, the loop is completely self-sustaining and ready to be repeated as many times as you desire.