Waveset synthesis is a Trevor Wishart invention – his Tongues of Fire is a fantastic example of the approach. It’s basically 20 minutes of variations on one 2-second input sound (him making monster sounds with his voice) plus some phase vocoder processing.
Doesn’t seem to be a full version in the clod, but someone uploaded the extras disc from the CMJ issue that has sound examples to archive.org – scroll down for the excerpts and keep in mind this was done in 1994!!
Here’s the article about that piece: https://www.jstor.org/stable/3681924 (and other pieces)
His book Audible Design goes into depth about his approach to waveset synthesis. I’ve been looking for a used copy of Audible Design for years… it’s not easy to find. I’ve never seen one available anywhere, not even a crazy expensive copy. Seems like the kind of thing you hold onto. I recently found a PDF scan of the main book on soulseek though, but it’s missing the appendixes… still very worth tracking down!