Sol Ring

Evelyn, the Covetous

Flash
Whenever Evelyn, the Covetous or another Vampire enters the battlefield under your control, exile the top card of each player's library with a collection counter on it.
Once each turn, you may play a card from exile with a collection counter on it if it was exiled by an ability you controlled, and you may spend mana as though it were mana of any color to cast it.

Arcane Signet

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