Epimer of glucose is
When sugars are different from one another, only in configuration with regard to a single carbon atom, other than the reference carbon atom, they are called epimers. For example, glucose and mannose are an epimeric pair which differs only with respect to C2. Similarly, galactose is the 4th epimer of glucose.Ref: DM Vasudevan, 7th edition, page no: 76
Fructose
Galactose
Glyceraldehyde
None
Metabolism of carbohydrate