An exciting feature of abcm2ps is the possibility of writing extensions as PostScript code. Some of the ABC files included in the abcm2ps distribution show examples of such extensions.
I have gathered some code and written a few .fmt files. I remind you that to use the code in external .fmt files one has to write this command line:
abcm2ps file.abc -F formatfile
where formatfile refers to the file formatfile.fmt.
There you are a list of my .fmt files, which will grow as I finish writing and testing them. They all work on both the stable and development abcm2ps releases. Kudos to Jean-François Moine for writing the original code!