Here are some useful subject terms Worldcat UMD uses for pedagogy:
You can combine any of these with your chosen instrument or instrument family (like "bowed stringed instruments" for more general resources).
Worldcat UMD and other library catalogs can be very picky about terminology. For example, you must use violoncello and double bass instead of cello and bass.
Subject headings allow you to search and browse through different genres and types of music. Here is a list of some subject headings in Worldcat UMD that you might find helpful:
To start searching, just replace the subject headings above with your instrument of choice (remember to use violoncello and double bass). Use "bowed stringed instruments" in place of a specific instrument for general string instrument materials. "String quartets" or other common ensembles can also replace a specific instrument to find various instrumental ensemble materials.