Appa, Steadfast Guardian + Umori, the Collector + Stone Calendar + Felidar Guardian

Appa, Steadfast Guardian

Umori, the Collector

Stone Calendar

Felidar Guardian

How it works

1. Cast Appa by paying
2. When Appa enters, its first ability triggers, exiling Felidar Guardian with the ability to cast it later from exile.
3. Cast Felidar Guardian from exile by paying 0.
4. Appa's second ability triggers, creating a 1/1 Ally creature token
5. When Felidar Guardian enters, it triggers, blinking Appa.
6. Repeat from step 2.