Magistrate's Scepter + Coretapper + Splinter Twin

Magistrate's Scepter

Coretapper

Splinter Twin

How it works

1. Activate Coretapper by tapping it, creating a token copy of it with haste.
2. Activate the token Coretapper's first ability by tapping it, putting a charge counter on Magistrate's Scepter.
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.