Every bride treasures her shower and wedding cards.  Many lovingly store them in a special box or binder.  Some even find crafty and creative ways to display them. 
Keepsake cards today shine with satin, lace, ribbons, rhinestones, sequins and even embroidery - three rhinestone "bubbles" hover over a line drawing of two champagne glasses, or the piece may feature fabric miniature attachments (a little ivory pillow carrying two tiny rings or a wedding cake made with layers of ribbon).
Even more treasured are the sender's handwritten wishes, especially when they reflect personal relationships with the bride and groom.  These words will be remembered always.