It is customary for the Bride and Groom to give gifts to their friends and family that are involved in the wedding. They do this to show their love and appreciation for helping to make their day so much more special.
Traditionally, at the rehersal dinner, bridesmaids are given jewelry to wear the day of the wedding and the groomsmen something to carry with them, like a pocketwatch. This tradition is nice but, does make it a bit harder to make those gifts personal.
It may take more thought and time, but you can show your appreciation more by making each person’s gift special to their own personality.