Case Western Reserve University Early Music Instrument Database
Database of medieval, renaissance, and baroque instruments, created by Dr. Ross W. Duffin.
International Music Score Library Project. (IMSLP/Petrucci Music Library)
The IMSLP was created to provide public-domain music scores free of charge to anyone with Internet access. It includes music scores in PDF versions; audio files of some pieces of music, with downloadable MP3 files; and music-related forums and a blog. Browse by composer; browse recordings by composer; and search by melody, instrumentation, or genre. As of Jan. 1, 2019, public domain includes items published before 1924.
Library of Congress. Performing Arts Databases.
Searchable research databases and catalogs related to the performing arts.
Society for Eighteenth-Century Music
An organization that promotes the study and performance of music from the 18th century.