Auxy Music Studio - Auxy brings real music creation to iPhone in a simple and inspiring format.
cassini - Polyphonic Synthesizer for iPhone/iPod touch
AudioKit Synth One - Free & Open-source iPhone/iPad Synth 🎹
zMors Modular - Full featured modular synthesizer for iOS
FL Studio Mobile - Create & save multi-track music projects on a smartphone
Ripple Maker - A coffee machine that turns selfies & photos into latte art