JC's ABC Mirror Directories
Here you'll find my mirrors of abc tunes that have appeared on the abcusers mailing list. Since this list is for discussions of abc notation, the files here tend to be "interesting" from a notational viewpoint.
If you don't have ABC software, you might like to try a tool that I'm working on that returns the tunes in various formats:
This will return the page you're looking at now, but the ABC files will be expanded to show all the tunes, and each tune will have a line of links that will return it in a number of different formats.