As displays improved the color table limitations became obsolete, as such some icons (especially those with color shadings) benifit by using full range of colors rather than limiting them to just the AIcons color palette. Only those that benift greatly are provided, and should only be used no direct or true-color displays.
The README files "xrdb", "twm" and "using", in the "docs" section of the library, contains information to make use of these icons in a typical X windows environment.
Specific Contribs: