AudioKit Synth One - Free & Open-source iPhone/iPad Synth 🎹
keezy - A colorful soundboard. Play with music.
Sampulator - Make (and record) beats on your keyboard
SoundGrail - SoundGrail Music App designed for pianists, guitarists, and DJs.
Logic Pro X - Music production.
Aftertouch - Aftertouch – 3D MIDI Controller created and published by Kevin Nelson.