maybe nail polish of the colour you're wearing and a nail file and glue (nothing worse than showing off a new wedding ring with a freshly chipped nail) also some jelly beans or something sugary if you have a "fainter" in your wedding party - my daughter is notorious at fainting on hot days. A pen and a small notepad can come in handy too.
When i was overseas i found little bags full of emergency items. i'm talking tiny. It has *lip balm *dental floss *breath freshener *emery board *clear nail polish *nail polish remover *hair spray *elastic *earring backs *stain remover *double sided tape *mending kit *deodorant towlette *bandaid *tampon *advil