MIDI Visualizer - Small cross-platform MIDI visualizer written in C++/OpenGL
MIDITrail - "MIDITrail" is a MIDI player which provides 3D visualization of MIDI datasets.
Euphony - Euphony is a web-based MIDI player and visualizer.
Piano Visualizer - Bring your piano music to life with this application.
Piano VFX - Free piano visualizer with advanced particle effects.
Chordana Play for Piano - Chordana Play for Piano is an app that allows you to learn piano with any MIDI-supported keyboard or the actual MIDI piano.