Keezy Drummer - Make a beat in seconds
WaveShop - Open source audio editor
BlokDust - Join blocks together to build sounds with this web-based music making app.
TwistedWave - TwistedWave is one of the unique audio editors that allow you to edit your music file online without any installation.
FL Studio Mobile - Create & save multi-track music projects on a smartphone
Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.