The Sulky thread that has a beautiful sheen is probably for machine embroidery. They make rayon and cotton.
Elastic thread, if it's over 2 years old, I wouldn't use it.
fusible thread, I have had some for 10 years and it's still good.
Isacord is usually embroidery thread.
Usually the top of the thread will tell what type it is. Also, watch out for thread that said Quilting. It may be for hand quilting only.
Sounds like got a deal. .