This page serves as a further material site for the publication mentioned below.
If you find a broken or outdated link, please let me know. Thanks.
A more comprehensive list of all kinds of MIR-related datasets can be found at www.audiocontentanalysis.org.
 Hendrik Schreiber. CNN-based automatic musical key detection. In Music Information Retrieval Evaluation eXchange (MIREX), Suzhou, China, October 2017.