Combat Celebrant + Displacer Kitten + Spellbinder + Hammer of Purphoros

Combat Celebrant

Displacer Kitten

Spellbinder

Hammer of Purphoros

How it works

1. Declare Combat Celebrant and the creature with Spellbinder attached as attackers, choosing to exert Combat Celebrant as it attacks.
2. Combat Celebrant triggers, causing you to untap all other creatures you control and to get an additional combat phase after this one.
3. Deal combat damage using the creature that has Spellbinder attached.
4. Spellbinder triggers, causing you to copy a card exiled with it, and cast the copy without paying its mana cost.
5. Displacer Kitten triggers, blinking Combat Celebrant.
6. Resolve the spell cast in step 4.
7. Repeat each combat phase.

This fascinating setup achieves infinite combat phases by cleverly bypassing Combat Celebrant's built-in restriction using Displacer Kitten. While Hammer of Purphoros grants your attackers haste to get things moving immediately, the true engine relies on the creature equipped with Spellbinder dealing combat damage to trigger a free copy of an imprinted instant. Because that copied spell is noncreature, it triggers Displacer Kitten's avoidance ability to blink Combat Celebrant, resetting its "exerted" status entirely so it can be exerted anew in the next combat phase.