Shower them with ornaments!
If you are hosting a bridal shower in December, why not make it an ‘holiday ‘ shower, if your bride is so inclined. The guests could bring beautiful ornaments as gifts: a great tree skirt; or a lovely menorah, special linens for the holidays. Gifts that help the couple establish their own holiday traditions can be so meaningful, and each celebration will remind them of the dear friends and family that shared the parties leading up to their wedding day.
Perhaps you could make dishes that are traditional with the families to serve at the shower (and have the recipes available for all!) What a wonderful way to start the couple’s life together!