Fairly obviously, I'd have thought, you could test a document via code like:
If .Font.ColorIndex = 9999999 Then
from where you might take an approach like that demonstrated in
https://social.msdn.microsoft.com/Fo...-word-document to compile a list of the colours in use (the code in the link tests for Styles, but the principle is the same). The main difference you'll need to consider is whether you need to return only colorindex values or whether you need to return values from the full RGB spectrum.