AudioKit Synth One - Free & Open-source iPhone/iPad Synth 🎹
Audacity - Audacity is a free and open-source audio production software suite that includes a surprising array of editing tools and recording systems.
Sampulator - Make (and record) beats on your keyboard
Ableton Live - Ableton makes Push and Live, hardware and software for music production, creation and performance. Ableton´s products are made to inspire creative music-making.
Splice Beat Maker - Make and share beats in your browser
Reaper - Reaper is a focused digital audio workstation (DAW) developed by Cockos. In the creation of the software, the digital audio technology company intended to make audio editing accessible to the masses.