Openwhyd - Collect and Share the tracks you love.
MuseScore.org - Create, play back and print beautiful sheet music with free and easy to use music notation software MuseScore. For Windows, Mac and Linux.
Zoff - Collaborate on a live music and video playlist with your friends.
Guitar Pro 7 - Create, play and share your tabs
SoundCloud - Enjoy music & follow favourite artists
Finale - Finale, the world standard for music notation software, lets you compose, arrange, notate, and print engraver-quality sheet music.