SoundGrail - SoundGrail Music App designed for pianists, guitarists, and DJs.
SunVox - SunVox is a small, fast and powerful modular synthesizer with pattern based sequencer (tracker).
keezy - A colorful soundboard. Play with music.
FL Studio - Image-Line's FL Studio, now on it's 12th version, is a well-known music production suite and the most popular beat processor on the market, due no doubt to its longevity. Read more about FL Studio.
Figure - Propellerhead creates world-class software products and services that inspire music makers and provide the foundation for a worldwide creative musical community.
FamiStudio - FamiStudio is very simple music editor for the Nintendo Entertainment System or Famicom. It is designed to be easier to use than FamiTracker, but its feature set is also much more limited.