Here are examples of different decorated mats. There's French lines and washed panels - a lovely traditional method of decorating mats using ruling pens, inks, and watercolor washes; embossed mats that feature multiple mats cut and stacked, then wrapped with fabric to make bas-relief like decorations; handpainted mats I do with acrylic paints directly on the mat surface; accented mats with die-cut design elements mounted on the mat. There's lots of other ways to add that special touch to a mat, the only limit is your imagination!