Yellow A Alternate cards are reprints of specific cards from several Pokémon Trading Card Game expansions featuring a yellow "A" symbol in the bottom right corner of the card. The symbol indicates the card has an alternate artwork.
Yellow A Alternate cards were first released in the Mega Powers Collection. This product included new Full Art prints of cards from the XY Series but the product itself was launched during the Sun & Moon Series.
While reprints with different artwork are usually printed as Black Star Promos, in some cases, this allows certain cards to stay legal in the Standard format for more time than it was intended. To prevent this, the yellow A symbol was introduced.
Yellow A Alternate cards have the same card number and expansion symbol of the original print with the exception of a letter added to the card number. As such, these alternate prints are only allowed in the same formats as the original print.
Initally, all Yellow A Alternate cards were reprints of cards from the XY Series, either being Full Art cards originally included in the Japanese The Best of XY subset or Trainer cards with English exclusive artwork. Later, they were made to utilize new artwork made for reprints within Japanese subsets or SM-P Promotional cards.