When LibreCAD was forked from QCAD, the icons were not allowed to transfer over. So a LibreCAD developer quickly pulled together the Lime green icon set that ships with LibreCAD. For the moment, those icons are sufficient and LibreCAD developers are working on improving drawing functions. The developers would prefer to create an icon theme setup similar to Inkscape. In this situation, the icons are stored in an SVG file and extracted via a script. This would be ideal because it would make it easier to maintain the icons. For now, the icons are added to a resource file and automatically scaled by the QT libraries as needed. This setup will continue until someone is motivated to improve the situation.
As for sodaCAD, the icons will need to be improved, both from a visual standpoint but also for usability. Some of the LibreCAD icons are confusing and need clarity. sodaCAD will over time need custom icons. So this is what I've started working on:
1. Convert current LibreCAD icons to the Tango Art Libre and/or Inkscape Tango-fied set.
2. Create icons for LibreCAD in which there are no equivalent icons in the Art Libre set, but which abide by the Tango guidelines.
3. Donate the new icon set back to the LibreCAD community.
4. Create custom icons for sodaCAD as needed.