I think most players that use an SD card for storage are limitted mainly by the count of files that can reside in root directory. I think for FAT16 it was about 512 entries. Most wav players (including my SimpleSDAudio library
) only work with 8.3-filename format, but this allows really getting those 500 entries on the card. If you need more, you have to take or patch a library to operate even with subfolders on card or use FAT32 formated cards. Then the limit is only the space available on the card.