As a Musician, I'll be more interested in style transfer: You give it a snare (or a multitrack drum loop !), and you tell it to generate a related hit-hat (or a complete kit !)
There is no shortage of samples and sample packs (millions), and most pros are picky : context in king, and style transfer is more contextual.
For instruments/synths/vox, "playability" is important, so the best approach IMO is cloning a sample to playable Midi instrument like midi-ddsp, midi2params or Mawf