Nerves.

There are many
             many
                        millions of nerves,

 

each one is a single cell but these are more correctly termed neurons. 

It is estimated that there are up to 100 billion neurons in the human brain.

It is likely that there are more neurons in the human body than any other cell type.

There are also the main named 'nerves'. 

These are the collections of individual cells that all follow the same anatomic route through the body (within a single connective tissue pipe or sheath); for example the sciatic nerve and the radial nerve.

There are three main types of nerves and, according to Wikipedia, 214 named nerves.

 Allowing for bilateral symmetry one could expect the answer to your question to be 428. 

However there are many unnamed nerves, such as those that run to small sensors in the skin or the periosteum, and many that are repeated many more times than twice (the intercostal nerve in yellow for example).

So the answer in fact must be that there are many thousands, but quite possibly millions, of bundles neurons.

 It is said that there are enough nerves in the human body that if all the other cells were somehow removed the network of fine nerves would be numerous enough to enable you to easily recognize the individual concerned and to recognize every tissue layer in his or her body.