Holotower

Holotower enters tapped unless you control a legendary creature.

{t}: Add {w}{r} or {u}{g}

{1},{t}: Add one mana of any color in your commander's color identity. If you spend this mana
to cast your commander, it enters with a number of additional +1/+1 counters on it equal to the number
of times it's been cast from the command zone this game.