projectM - projectM is an LGPL'ed reimplementation of Milkdrop under OpenGL.

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.

Magic Music Visuals - Fully-customizable and highly responsive visuals for live and recorded audio & MIDI.

SunVox - SunVox is a small, fast and powerful modular synthesizer with pattern based sequencer (tracker).

Kauna - Kauna is a music visualizer. Kauna renders any sound reproduction in system.

Cubasis - Cubasis is Steinberg’s streamlined, multitouch sequencer for the iPad.