You want to match your thread to your fabric in both colour and fibre. Cotton thread for natural fibers, polyester thread for synthetic blend fabrics, silk thread for silk fabric etc. You also need to consider if you want a matte thread finish (cotton thread) or shine (rayon) or a glimmery metallic thread.
Cotton - Cotton thread can stand an incredible amount of heat from an iron, which is key when pressing cotton fabrics. The most popular choice with quilters.
Polyester - Polyester thread is a true all-purpose thread. Also a popular choice with quilters and less expensive than cotton.
Silk - Silk thread is very fine, perfect for sewing silk fabric.
Metallic Thread - Often used for topstitching, but be careful when ironing over metallic thread - always cover with cotton cloth before ironing
Monofilament - This is a sewing thread that looks invisible when stitched into fabric.