Giada - Giada is a free, minimal, hardcore audio tool for DJs, live performers and electronic musicians.
Keezy Drummer - Make a beat in seconds
JAM - Shake your sound - Music motion app. Make music by shaking your phone. 🎶
Sampulator - Make (and record) beats on your keyboard
Roland 808303.studio - TR-808 drum machine and TB-303 bass synthesizer emulator
Auxy Music Studio - Auxy brings real music creation to iPhone in a simple and inspiring format.