Logic Pro X - Music production.
MilkyTracker - MilkyTracker is an open source, multi-platform music application for creating .MOD and .
AudioKit Synth One - Free & Open-source iPhone/iPad Synth 🎹
OpenMPT - OpenMPT is a popular tracker software for Windows.
Sampulator - Make (and record) beats on your keyboard
FamiStudio - FamiStudio is very simple music editor for the Nintendo Entertainment System or Famicom. It is designed to be easier to use than FamiTracker, but its feature set is also much more limited.