Music

Mutopia Project
Free Sheet Music for Everyone, 2098 pieces of music, free to download, modify, print, copy, distribute, perform, and record – all in the Public Domain or under Creative Commons licenses, in PDF, MIDI, and editable LilyPond file formats.

IMSLP
Petrucci Music Library. Sharing the world’s public domain music.  131,017 works · 16,216 composers · 473 performers
428,481 scores · 8,980,453+ pages · 49,814 recordings