Saheeli, the Sun's Brilliance + Mana Echoes + Chromatic Orrery + Sparring Mummy

Saheeli, the Sun's Brilliance

Mana Echoes

Chromatic Orrery

Sparring Mummy

How it works

1. Activate Saheeli by paying 2 and tapping it, creating a token copy of Sparring Mummy with haste.
2. When the token Sparring Mummy enters the battlefield, it and Mana Echoes trigger.
3. Resolve the Sparring Mummy trigger, untapping Saheeli.
4. Resolve the Mana Echoes trigger, adding C for each creature you control that shares a creature type with Sparring Mummy.
5. Repeat.