Jegantha, the Wellspring + Horde of Notions + Yahenni, Undying Partisan + The Fire Crystal

Jegantha, the Wellspring

Horde of Notions

Yahenni, Undying Partisan

The Fire Crystal

How it works

1. Activate Jegantha by tapping it, adding that cannot be spent to pay generic mana costs.
2. Activate Yahenni by sacrificing Jegantha.
3. Activate Horde of Notions by paying , causing you to cast Jegantha from your graveyard without paying its mana cost.
4. Repeat.

This clever loop uses Horde of Notions as an engine, tapping Jegantha, the Wellspring for the exact five-color mana requirement needed to cast Horde of Notions' activated ability. By feeding Jegantha to Yahenni, Undying Partisan as a sacrifice outlet, you trigger Yahenni, Undying Partisan's ability to grow while sending Jegantha straight to the graveyard so the Horde can immediately replay it for free. Meanwhile, The Fire Crystal sits quietly in play, providing haste to make sure everything can move at a moment's notice even though the core loop's mana is strictly color-restricted.