watch fob
A short chain or ribbon with an attached medallion or ornament that connected to a man’s pocket watch and hung from a small pocket in his waistcoat. Men often wore several fobs, along with seals and other ornaments, clustered together on a single chain or ribbon.
The print shows a detail of "Concert Dresses" from Le Beau Monde, September 1807, where the gentleman is wearing two fobs on a gold chain.