Blightbeetle + Zedruu the Greathearted + Yahenni, Undying Partisan

Blightbeetle

Zedruu the Greathearted

Yahenni, Undying Partisan

How it works

1. Donate Blightbeetle to an opponent
2. Activate Yahenni by sacrificing the undying creature.
3. When the undying creature dies, its undying ability triggers, returning itself from your graveyard to the battlefield without a +1/+1 counter on it due to Blightbeetle.
4. Resolve the Yahenni ability.
5. Repeat from step 2.

This clever loop turns Blightbeetle's passive hate into a powerful asset by using its clause preventing your opponents' creatures from getting +1/+1 counters to permanently suppress the self-buff drawback of an undying creature. With that safety net in place, you can repeatedly feed that creature to Yahenni, Undying Partisan's sacrifice ability to farm infinite death and trigger counts while keeping Yahenni safe with indestructible. Meanwhile, Zedruu the Greathearted smiles upon your board state, allowing you to donate Blightbeetle to an opponent so that Zedruu's upkeep trigger scales massively with every permanent you've handed away.