Here's a way to both keep and use a stack of special cards:
Using strong ribbon of whatever length is long enough to display all the cards, make a garland by machine stitching along the folds of the cards. Make sure they all are positioned with the front of the cards facing outward.
To the right, note the penguin toddler pajamas which I mended right before doing this craft. :o) *ha ha ha* I hadn't noticed that they made it into the picture until now.
The third photo here shows a card as it is being stitched to the ribbon: the card is all the way open under the presser foot of the machine.
I made 2 garlands - one which is made of New Baby cards, one of baptism cards. These can be strung up as decorations at her birthday if we want, or on her baptismal anniversary.
I think this is a good way to make use of the pretty cards rather than have them either get lost or languish in a file folder for the rest of our lives...this would be a good idea for wedding cards, too - I could make garlands out of them and string them up on our anniversary each year.