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.
NtEd - Music Score Notation editor.
Sibelius - Sibelius is a virtual score creation tool which allows composers to easily create new piano scores, developed by Avid.
MuseScore - Our goal is to let musicians from all over the world create and share their works, as well as to make learning music exciting, easy and available for all.
DaCapo Editor - DaCapo Editor is a free Open Source music sheet editor which allows to easily create nice looking partitions. It is available as a web application as well as a desktop application for Windows, MacOS and Linux.
Guitar Pro 7 - Create, play and share your tabs