Auxy Music Studio - Auxy brings real music creation to iPhone in a simple and inspiring format.
SoundGrail - SoundGrail Music App designed for pianists, guitarists, and DJs.
AudioKit Synth One - Free & Open-source iPhone/iPad Synth 🎹
keezy - A colorful soundboard. Play with music.
FL Studio Mobile - Create & save multi-track music projects on a smartphone
Splice - Music creation, collaboration, and sharing made simple.