Urza, Prince of Kroog + Coretapper + Magistrate's Scepter

Urza, Prince of Kroog

Coretapper

Magistrate's Scepter

How it works

1. Activate Coretapper's first ability by tapping it, putting a charge counter on Magistrate's Scepter.
2. Activate Urza by paying 6, creating a token copy of Coretapper that is a 1/1 Soldier.
3. Activate the token Coretapper's second ability by sacrificing it, putting two charge counters on Magistrate's Scepter.
4. Activate Magistrate's Scepter's second ability by tapping it and removing three charge counters from it, causing you to take an extra turn after this one.
5. Repeat each turn.