1. Glucose: Glucose is the most common monosaccharide and is the body's primary source of energy. It is found in many foods, including fruits, vegetables, and grains.

2. Fructose: Fructose is a naturally occurring sugar found in fruits and honey. It is sweeter than glucose and is often used as a sweetener in processed foods and beverages.

3. Galactose: Galactose is a monosaccharide that is found in milk and milk products. It is also found in some fruits and vegetables.