Seal a photo, print, dried flower petals, etc., under resin.
Research copyright free astrological star sign charts. Solder small bits of balled wire to the bezel back to mimic your astrological sign.
Put some glue in the bottom and sprinkle on gemstone chips for a "druzy" look-alike.
Change the shape of the backing, add two connectors, put a domed disc inside the bezel, and add a few embellishments, and the bezel becomes a link.