Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Vraska, the Silencer

Deathtouch
Whenever a nontoken creature an opponent controls dies, you may pay {1}. If you do, return that card to the battlefield tapped under your control. It's a Treasure artifact with "{T}, Sacrifice this artifact: Add one mana of any color," and it loses all other card types.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Command Tower

{T}: Add one mana of any color in your commander's color identity.