Time Sieve + Mycosynth Lattice + Helm of the Host + Avenger of Zendikar

Time Sieve

Mycosynth Lattice

Helm of the Host

Avenger of Zendikar

How it works

1. At the beginning of your combat phase, Helm of the Host triggers, creating a token copy of Avenger of Zendikar with haste.
2. The Avenger of Zendikar token enters the battlefield, creating a 0/1 Plant creature token for each land you control.
3. Activate Time Sieve by tapping it and sacrificing five creature tokens, causing you to take an extra turn after this one.
4. Repeat each turn.