Vanquisher's Banner

As this artifact enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

The Lost Caverns of Ixalan Commander

As Vanquisher's Banner enters the battlefield, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

The List

Commander Masters

"Seven stars and seven stones and one white tree."
—A rhyme of lore

Tales of Middle-earth Commander

March of the Machine Commander

The choice of creature type is made as Vanquisher's Banner enters the battlefield. Players can't respond to this choice. The bonus starts applying immediately.

The last ability of Vanquisher's Banner resolves before the spell that caused it to trigger. The ability will resolve even if the creature spell is countered.

Because damage remains marked on a creature until the damage is removed as the turn ends, nonlethal damage dealt to a creature you control of the chosen type may become lethal if Vanquisher's Banner leaves the battlefield during that turn.

To choose a creature type, you must choose an existing creature type, such as Fungus or Sliver. You can't choose multiple creature types, such as Fungus Sliver. Card types such as artifact can't be chosen, nor can subtypes that aren't creature types, such as Jace, Vehicle, or Treasure.