Monosaccharides such as fructose and galactose are widely used individually throughout the body, despite their chemical simplicity, unlike amino acids, fellow biological building blocks. However, like amino acids, monosaccharides have many useful derivatives. There are six ways in which derivatives of monosaccharides can be formed:

Sugar phosphates:
Phosphate esters of sugars, found significantly in metabolic pathways. Produced through hydrolysis of an acid and an alcohol, then attatched by hydrolysis again to the monosaccharide. Naming conventions attach the number of the carbon serving as the linkage and the number of phosphates. For example, with a glucopyranose monosaccharide in ring form, one can have α-D-Glucopyranose-6-phosphate, α-D-Glucopyranose-1,6-bisphosphate, α-D-Glucopyranose-1,5,6-trisphosphate, etc.

Deoxy sugars:
One of the OH groups of the monosaccharide is replaced with hydrogen. An example of this is, coincidentally, DNA. Did you know the long ass name deoxyribonucleic acid is actually a shortening of the even longer ass name β-2-deoxy-D-Ribofuranose nucleic acid?

Amino sugars:
One of the OH groups is again replaced, except this time with an amino group, NH2. An example of one of these is α-D-glucosamine, used in cartilage.

Sugar alcohols:
Created through the reduction of the carbonyl oxygen to a hydroxyl group. A polyhydroxy alcohol is produced. The naming convention is to disattach the standard carbohydrate 'ose' ending and replace it with 'itol'. So, for example, ribose goes to ribitol.

Sugar acids:
In these derivatives, either the aldehyde carbonyl is oxidized to COOH, or the highest number carbon is oxidized to COOH.

Ascorbic acid
This is a unique one. Ascorbic acid is really just another name for vitamin C. The molecule is a derivative of D-glucoronate.