Cogwork Assembler + Coretapper + Magistrate's Scepter

Cogwork Assembler

Coretapper

Magistrate's Scepter

How it works

1. Activate Cogwork Assembler by paying 7, creating a token copy of Coretapper 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.

This infinite turn engine is built around Magistrate's Scepter, which demands a steady influx of charge counters to repeatedly grant you extra turns. Since hard-casting those counters is far too mana-intensive, Cogwork Assembler steps in to repeatedly forge temporary artifact copies of Coretapper using its steep activation cost. You then leverage the original Coretapper and its freshly minted token copy to supply the exact number of charge counters Magistrate's Scepter needs, sacrificing and tapping them to fuel the cycle every single turn.