NAD acts as a cofactor for all except
Niacin (Vitamin B3) in biologically active form of NAD+ (nicotinamide adenine dinucleotide) and NADP+ (nicotinamide, adenine dinucleotide phosphate) act as cofactor for various enzymes such as
NADP+ Cofactor

Glucose-6-phosphate dehydrogenase (G-6-PD (glucose-6-PO4 to 6-phosphogluconate)
Glutathione reductase

Either NADP+ or NAD+  Cofactor


Glutamate dehydrogenase (glutamate → α-ketoglutarate + NH3)
Isocitrate dehydrogenase (isocitrate → oxalosuccinate) 

NAD+ Cofactor

Malate dehydrogenase (malate → oxaloacetate)
Alcohol dehydrogenase (ethanol → acetaldehyde
Lactate dehydrogenase (pyruvic acid → lactic acid)
Glyceraldehyde-3-phosphate dehydrogenase (glyceraldehyde 3P →1, 3 diphosphoglycerate)
α - Glycero-P-dehydrogenase
α -Ketoglutarate dehydrogenase (α – ketoglutarate → CoA)
Pyruvate dehydrogenase complex (PDC) (pyruvate →  CoA)
Isocitrate dehydrogenase
Alpha ketoglutarate dehydrogenase
Malate dehydrogenase
Succinyl thiokinase