Auxy Music Studio - Auxy brings real music creation to iPhone in a simple and inspiring format.
BeatStyle - A mobile recording studio!
cassini - Polyphonic Synthesizer for iPhone/iPod touch
Groovebox: Beat & Synth Studio - Make Music & Play Instruments
zMors Modular - Full featured modular synthesizer for iOS
VOXISO - Online AI-powered vocal and music remover