I imagine myself in my office with all my documents and a shredder. Documents currently in the shredder and going to be either the most current stuff I have or some old archive that I decided I no longer needed to keep in hard copy.
As long as I am unaware that I am about to be raided, the current content of my shredder would probably have little use to investigators. So, unless Michael Cohen was tipped off, I doubt there will be much in there.
On the other hand, everything else that was confiscated may contain a goldmine of data.