Sorry, I thought you were referring to the floppy drives not the disks themselves. Patchman Music have a couple of banks available for sale http://www.patchmanmusic.com/yamahaDX7II.html and Greytsounds have 4 sound sets available at http://www.greytsounds.com/gs/ssi/ssi-yamaha2.html?CXT=2076758511

But other than these you won't find many others around for this synth nowadays but there are 1000s of free DX7 patches available online that you could use to build your own DX7II patches yourself.