make bookmarks, we do this to give as token gifts when I need a lot of little giveaways for people
make Christmas tree ornaments, or gift tags
exceptionally pretty scenes can be used in decoupage if you are crafty
granddaughter made me a cute box which she decorated from images cut out of greeting cards, all birds.
give them to your CCD director or classroom teacher for crafts.
I have a set of illustrations of mysteries of the rosary on flash-cards made from greeting card images (also used some calendar illustrations–calendars are another thing I like to have donated if the pictures are good).
some crafts we have made using greeting cards:
Nametags for CCD or VBS
re-use cut-out images to make new greeting cards
to illustrate placemats, baskets, fans, gift boxes and other crafts
covers for journals, folders or scrapbooks
we built Marian shrines in VBS one year
we built a church in one class, and used greeting card images for saint shrines and stained glass windows.