EarMaster - Professional software for ear training and practical music theory on Windows and Mac.
Amper Music - Artificial intelligence music composer
GNU Solfege - GNU Solfege is free music education software.
Bandlab - Capture, nurture, and collaborate on song ideas in the cloud
LenMus - LenMus is a free program for learning music.
WaveBots Editor - Procedural music and sound maker that exports to Wav, MIDI, GoatTracker and much more.