Stalwart Successor + Putrid Goblin + Yahenni, Undying Partisan

Stalwart Successor

Putrid Goblin

Yahenni, Undying Partisan

How it works

1. Activate Yahenni by sacrificing Putrid Goblin
2. When Putrid Goblin dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
3. When Putrid Goblin enters, Stalwart Successor triggers, putting a +1/+1 counter on Putrid Goblin
4. Resolve the Yahenni ability.
5. Repeat.