Command and accounting
A stream editor in java that can handle text/binary formats
A .NET/Mono library for string-based user interface localization.
This program is a budget editor/creator for building
Virtual paper folding program
An STL model viewer, editor, and creator for manipulating STL files.
Pixel font editor for embedded projects
Lego Island 2 Game Editor
Marching drill design for the modern connected age.
IRB is a game creation toolkit
NSD graphical editor, for Java development and rev-engineering
Grid-based Java medieval RPG map editor & battle system
Very basic text editor
The latest sources of Colin Wilsons's XN Resource Editor
Discriminative language editor based on ontologies
a clean Python Editor
DocBook Editing and Processing for Eclipse
Electronic design and programming tools suite like Eagle, MpLab
Development of a plugin based dev tool for RPG Maker
yEdGen can open a flow chart and generate ANSI C code from it.