Is NADH found in all type of cell in human body?
As NAD+/NADH is involved in both glycolysis and in the tricarboxylic acid cycle it is difficult to imagine any cell capable of generating energy not having some NADH. (Are there any cells that are not capable of this? Calcified cells such as bone?)

A quick internet search for ‘microglia’ and ‘metabolism’ indicates that microglia have energy metabolism and so I would expect them to have NADH. How much (compared to NAD+) would depend on their metabolic state.