JavaScript client-side editor for general diagramming & whiteboarding
Audio Tag Editor
Flowchart editor
User flow chart real-time collaborative tool
JavaScript Sequence Editor
an Open Source BPMN 2.0 / DMN 1.1 Modeler
Playlist Editor
Shotcut is a free, open source, cross-platform video editor.
audio sequencer
A free multi-track audio editor and recorder
Model Railway CAD program
Graphical editor software for many Boss and Roland effect & synth unit
Snd is a sound editor
EasyABC is an open source ABC editor
Nyquist is a language for sound synthesis and music composition.
Another drawing editor for LaTeX with PSTricks & TikZ
Open Source Solid Modeling CAD
Reorganize M32/X32 show files
View64 is a image viewer for C64 images
Quimup is a Linux client for MPD
show and edit eulumdat files
Java3d scenegraph editor