SWad
SWad is an extremely basic Doom wad lump manager, written in Visual Basic. I didn't get too far with this one, the last release was 0.2 beta, before I abandoned it to begin work on SLADE, and eventually SLumpEd.
The main point to it was to be able to import/export lumps without any data conversion happening, something which other lump managers at the time seemed to fail at. SLumpEd and SLADE 3 both follow this rule too - nothing is automatically converted on import/export.
The source code for this is long gone unfortunately, however 0.2 beta binaries can be downloaded here. Note that it requires some VB ocx files to be registered to run.