Elite Arcanist + Seething Song + Chromatic Orrery + Pemmin's Aura

Elite Arcanist

Seething Song

Chromatic Orrery

Pemmin's Aura

How it works

1. Activate Elite Arcanist's ability by paying 3 and tapping it, casting a copy of Seething Song without paying its mana cost.
2. Resolve Seething Song, adding 5.
3. Activate Pemmin's Aura's first ability by paying 1, untapping Elite Arcanist.
4. Repeat.

This clever loop centers around Elite Arcanist, which you must first prime by exiling Seething Song as it enters the battlefield. With Chromatic Orrery in play letting you spend your mana as any color, tapping the Arcanist lets you cast a copied Seething Song to generate a surge of mana. Pemmin's Aura then steps in to untap Elite Arcanist for just a single blue mana, allowing you to repeat the process indefinitely for infinite red mana, storm count, and magecraft triggers.