Painter's Servant

As Painter's Servant enters, choose a color.
All cards that aren't on the battlefield, spells, and permanents are the chosen color in addition to their other colors.

High Tide

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

Grindstone

{3}, {T}: Target player mills two cards. If two cards that share a color were milled this way, repeat this process.

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Sol Ring

Richard Garfield, Ph.D.

You may play cards as though they were other cards of your choice with the same mana cost. You can't choose the same card twice. (Mana cost includes color.)