There is a lot of speciality thread types used in embroidery these days. The selection ranges from polyester to rayon and everything in between; providing various options to create different embroidery styles and designs.
Specialty Threads can be used for Designing and Decorating:

Solar Color-Change
Using Solar Color- Change specialty threads is an amazing way to surprise people. This type of thread appears white if not directly hit by sunlight or other UV rays. When exposed to UV, they change colors and create a surprising and excellent twist to every outfit—showcasing the colorful embroidered design.
Glow-in-the-Dark
Used best in children’s pajamas and other kid’s clothing, this glow in the dark specialty thread adds fun to every dress or embroidered accessory when the lights are off. Outfits embroidered with this type of threads are also great for outdoor night activities.
Metallic Threads
For shine and luster, some people like having metallic specialty threads on their outfits. They have a reflective fiber that goes perfectly with darks shade dresses and outfits. For example adding silver metallic embroidered design to a casual black dress can give it an elegant touch perfect for cocktail events.
Multicolored
Those who love adding colorful designs to plain colored outfits and accessories would probably prefer a multicolored specialty threads. For these threads come in various color combinations i.e. rainbow color variation, specific color shade variations, and other combos.
With the use of these specialty threads i.e. Solar Color-Change, Glow-in-the-Dark, Metallic Threads, and Multicolored, you can make embroidered designs and decors more fun, exciting and fashionable.