1. Flat Sheet: This is the top sheet that you lay on top of yourself when you sleep. It is usually larger than the fitted sheet and is rectangular in shape.
2. Fitted Sheet: This is the sheet that goes over your mattress and has elastic corners to keep it securely in place. Fitted sheets come in various sizes to fit different mattress heights.
3. Pillowcases: These are the covers for your pillows. Pillowcases come in standard size, queen size, and king size.
4. Comforter or Duvet Cover: Depending on the set, a comforter or duvet cover may be included. A comforter is a thick, quilted blanket that goes on top of the sheets to provide warmth. A duvet cover is a decorative cover that goes over a duvet insert, which is a down or synthetic-filled blanket.
5. Shams: These are usually included when a comforter or duvet cover is in the set. Shams are decorative covers that go over your sleeping pillows.
6. Bed Skirt: A bed skirt is a decorative piece that goes around the bottom of the bed to hide the bed frame and box spring.

Another important consideration is the type of material used for the sheets. The most common materials are cotton, polyester, and bamboo. Cotton is a popular choice as it is breathable, soft, and durable. Polyester is less expensive than cotton, but it is not as breathable. Bamboo is a sustainable and eco-friendly material that is also soft and breathable.