This is a miracle using two packs of cards (one Red the other Blue), whereby a card freely chosen from one pack, is revealed as the only card to be missing from the other pack. Then as a kicker finish, the card is turned over by a spectator and its back matches the colour of the second pack. Both packs are on display at all times, It's easy to perform and only two packs are used with no switching of card or cards.
(Note: This entire trick is also fully explained on page 155 of the excellent book 'Dave Campbell Legacy'. Simply purchase that book and you'll have this among the many other amazing card tricks and you can use your own playing cards).