KeyCastr, an open-source keystroke visualizer
Interactive error messages for the Julia REPL
SADSA (Software Application for Data Science and Analytics)
A plugin to use Free Sketches with SysML models to support MBSE
Spectroscopy Viewer
Simple interactive menus for the terminal (Now ships with Julia!)
3D Charts - Templates for PovRay(TM)
An interactive pi walk.
jchart2d is a real-time charting library written in java.
On-screen keyboard that highlights keys that are pressed.