Yamaha DX100 Resources
The Yamaha DX100 can store 24 custom voices internally. It receives and loads these voices in a MIDI bank file that actually stores 32 voices, but only the first 24 are used.
Patches
4 Op H.Q. has a lot of free DX100 banks for download (as well as for other Yamaha 4-op FM synths).
Patch Base has a full-featured Yamaha DX100 editor and librarian for both Mac and iPad. Try it out for free.