Rick Schneblin has created something very imaginative and interesting - a GPO Icon set for Garage Band! There are a total of 35 instrument icon sets in this collection that correspond to GPO Instruments. Very well done and highly recommended for Garage Band users!
Below is a screenshot of a few example tracks using the GPO_Icon Set
What Rick did was create replacement icons for all the dull and rarely used icons that come with GarageBand. Unfortunately, there is no way to "add" icons to GarageBand, only replace. You will need GarageBand to see these results. Rick also created an instruction sheet to get the Apple user started.
Here is the link to the icon set:
Feel free to download and try them out. If you find you are regularly using them, it would be great to give support Rick with a $10 shareware donation. Small price to pay for something so cool!