Calligraphy is the art of handwritten lettering originating from historical periods and cultures, using a range of scripts for different effects, in the same way that a printer uses varying fonts. Illumination is the name given to the process of decorating the text (particularly the initial letter) with figures, forms or patterns. At its highest level, illuminated lettering is embossed with 14-carat gold leaf and enhanced with figures of people or animals, relevant to the text.
As it is labour intensive, consider using a calligrapher to design all of your stationery for bulk printing, perhaps then adding gold leaf by hand.
If you are organised enough to arrange your table plan in advance, a calligrapher can re-produce it as a work of art, to display on the day, and for framing as a permanent momento.