Gauntlet of Power

As this artifact enters, choose a color.
Creatures of the chosen color get +1/+1.
Whenever a basic land is tapped for mana of the chosen color, its controller adds an additional one mana of that color.

Dominaria Remastered

As Gauntlet of Power enters the battlefield, choose a color.
Creatures of the chosen color get +1/+1.
Whenever a basic land is tapped for mana of the chosen color, its controller adds an additional one mana of that color.

The List

Time Spiral Remastered

Because damage remains marked on a creature until the damage is removed as the turn ends, nonlethal damage dealt to a creature of the chosen color may become lethal if Gauntlet of Power leaves the battlefield during that turn.

If Gauntlet of Power is somehow on the battlefield with no color chosen for its first ability, no creatures get +1/+1 and its last ability never triggers. It still won't affect colorless creatures or basic lands tapped for colorless mana.