Felidar Guardian + Sister Hospitaller + Yahenni, Undying Partisan

Felidar Guardian

Sister Hospitaller

Yahenni, Undying Partisan

How it works

1. Cast Felidar Guardian by paying its mana cost.
2. When Felidar Guardian enters the battlefield, it triggers, targeting Sister Hospitaller
3. Holding priority, activate Yahenni by sacrificing Felidar Guardian.
4. Resolve the Felidar Guardian ability, blinking Sister Hospitaller
5. When Sister Hospitaller enters, it triggers, returning Felidar Guardian from your graveyard to the battlefield and causing you to gain 4 life.
6. Repeat from step 2.