I found this post on another site: (It is not my post, so I can't answer questions about it). As follows: 428 Free Extra Rhythms (& Rhythm Editor) for Casio CTK-5000 & 4000
Just a heads-up for you CTK-5000 (& CTK-4000) owners. I went to the URL listed in the manual, where you can supposedly download extra tones, tunes, rhythms, etc. for various models of keyboards. http://music.casio.com/ But I found no files for the CTK-5000 there.
So ... I did a little experimenting. None of the tone and other files there work (except for the few SMF MIDI files), but ALL the rhythm files work just fine. They have a CKF file extension on them which isn't mentioned anywhere in the documentation on the CTK-5000 for allowable file-types. But Casio's Data Manager for this keyboard recognizes them just fine, and sends them to the User Rhythm slots, numbers 201-210.
They all include intros, fills, variations, and lead-outs. Some of them are very nice!
Be sure to get all of them. Even though some for different models of keyboards may be named similarly, but prefaced by RHY_, they are different rhythm arrangements. I suggest using your favorite batch file-downloader to cue them all up from the resulting URL that opens up when you click on each "Data List" button.
These will probably work for the CTK-4000 too, because both models use the same manual, the only main differences being the SD card and pitch-bend wheel.
p.s. I just found out that you can also save them as-is on your SD card and load them from there. The keyboard recognizes that file-extension just fine too. No need for a PC to load them, take them with you.
p.p.s. I just did a binary file compare of some with the exact same filenames from different keyboard models. A few have different byte counts, drastically different. So raise that count to 179 Free Extra Rhythms. I'm now wondering if I might have missed some before. If anyone gets a higher count than that, let me know if I missed any.
UPDATE: I found some more, and a utility to edit them all. On the Euro Casio site they have them available in zip packs for each keyboard model number.
Doing a binary file compare with the ones available at the first link mentioned to get rid of any duplicates, with these 3 more zip packs, it comes to a total of 428 unique rhythm files. With the 200 included in the keyboad, that's 628 rhythms, far beyond anything being offered in their latest 6000 and 7000 models.
You might also be interested in their IDES (Internet Data Expansion System) programs for other keyboard models. They won't talk to the CTK-4000/5000 directly, but they include a rhythm editor and CKF <-> SMF format conversion tool. It also allows you to access files on an SD card on your computer instead of a keyboard.