The Overmind, Eternal Will of the Swarm is all colors.

{t}: Add two mana of any color.

Eternal Will — Opponents can't gain control of Zerg permanents you control.

Assimilate — {1}{W}{B}{G}, {t}: Return a creature card from any graveyard to the battlefield under your control with a finality counter. That creature is a Zerg in addition to its other types.

The Overmind, Eternal Will of the Swarm can be your commander.