The Public Domain Music Library

imslp

Albeit online since 2006, I’ve never heard of this site before today. Known as the International Music Score Library / Petrucci Music Library, it contains over 13,335 works and 23,822 scores to date. Most of them, as one might expect, are works which have fallen in the public domain, but many others are copyrighted works licensed under one the different Creative Commons License flavours.

But beware that different countries have different laws over what we commonly know as "public domain". Their Wiki has an very informative page about the issue.

 

Found it while searching for a Canon in D transcription for piano.

 

 

[Link: The International Music Score Library Project (IMSLP) – http://imslp.org/ ]