When I discovered that I needed to make Open Metronome WAV-based, I had a heck of a time finding a GPL sample library that covered the complete General MIDI Percussion voice set. I'm providing this page for anyone who has the same problem, and also as a repository of sample-sets for Open Metronome. To use these in Open Metronome, just copy them into the "Samples" folder where the application itself lives (usually C:\Program Files\Open Metronome).
[Download] Free Human Beatbox General MIDI Percussion Samples.
This set is based on Frank Wen's pro-quality GM/GS soundfont. I used some tool to get the WAVs back out of the soundfont, gave them Open Metronome-compatible names, and here we are.
[Download] Free "Pro-Quality" General MIDI Percussion Samples.