Unlike the NES Sound Effect and Bumper Explosion, these are not necessarily sound effects, phrases, or samples that may be recognized as vocal, percussive, or even musical. The majority of these are small chunks of sample data used to construct wavetable instruments and sound effects using specific looping, pitch, and amplitude techniques.
Our friends Fox McCloud, Falco Lombardi, Slippy Toad, and Peppy Hare all speak using the same single short waveform, looped and played back at different frequencies:
Though there are also plenty of useful percussion and one-shot samples, like bass samples, some good and often goofy sfx, and even some lo-fi drumloops. The space used to store the sounds needed for music and audio playback is quite limited, so the designers had to be pretty thrifty and creative with how they used it. Of course, their goal was to make the music and sound as great as it could be (usually), so this exported collection of sounds represents a lot of interesting and difficult work, though it will take a bit of effort to make good use off them yourself. Personally, I really enjoy their inherent character and limitations.
This track, for example, uses solely the SMB RPG wavetable and Renoise:
I couldn't quite figure out how have the gui talk back to the script to let it know the rom had been loaded, scanned, and ready for export, and if I didn't set a delay between steps, I saw it sometimes skipping the export, so I had to set it to several seconds on a slower system, multiplying the time to complete the entire batch to nearly twenty hours for all ~12,000 roms; each with an average of 100 samples. I could do some additional research to optimize it, and I could have excluded the duplicate roms, or even dug even deeper to curate a collection of what I consider to be the best sounds, but I figured I'd just shove the entire collection out there, and let others do what they want with it.
For some reason the app wouldn't exit normally, so I simply killed it at the end of each export.
I put some additional effort into removing the thousands of silent files which existed for no known reason, and, in the process, converted them all to .flac which might make some people hateful, but both renoise and ableton support flac, and I don't know what other future these sounds have, so let me know if you need help converting them to wav or some other format I'm done with.