The bodies of the shirts are usually lycra, with satin or ultrasuede collars and cuffs.  Pictured below are a number of the fabrics I currently have available.  I visit the wholesalers from time to time and often have new fabrics that might not yet be shown here.

The riding jackets are usually ultrasuede, with leather or suede trim.  I can get garment leather in most popular colors.

And then don't forget the decoration!  There a lots and lots of options for decoration.  Gold or silver nailheads, studs, sequined cording, leather overlays, and of course Swarovski crystals of various shapes, colors, and sizes.  The only limit is your imagination.