Hi Jim,
The easiest and 'fun' way around this is to get yourself a spiral notepad (known as shorthand pads) go through every single sound and rhythm (including the music Stylist, Custom Stylist etc.) on your keyboard and make a note of the more obvious tunes you associate with the rhythm you are currently using.
Everytime I purchase a new keyboard/piano I always do this because it's impossible to remember all that is available on the keyboards and this way you soon build up your very own 'favourties' list.
Another thing I do is if I find an interesting rhythm (say a Country) I'll get a book of tunes and play right through it using that same rhythm. You will be surprised at the amount of different tunes that can be played using the same rhythm. By the same token, a number of rhythms can be played to the one tune. It might be time consuming but I can assure you it's an easy and fun way to learn plus you quickly become familiar with the 'layout' of the keyboard.
Once you have accumulated a list of 'favourites' there is a way of saving these to the Music Stylist and I think it is detailed in the Manual. I know how I do it but if I tell you now, it could confuse you so I'll check the Manual first.
Meanwhile, happy playing.
Audrey