The only cards that can be counted toward the event mission progress are the promo cards ‘Chansey’ and ‘Meowth.’ The cards that are counted have a "Chansey" icon on the lower right of the illustration. You can check the promo cards using the following steps: Home screen (leftmost button at the bottom of the screen) > Mission icon (rightmost button at the bottom of the screen) > Event > Tap the relevant mission.