Likely therefore this will end up being a brand new icon theme? What i would recommend is for you to start thinking on how to name it and on were to host the artwork. As forum attachments approach can quickly become inefficient for such tasks. And ideally to start providing icons as standalone files. As for how to name the files. Download or clone the FreeCAD repository. Lets say for Arch module:
If you browse to Arch/Resources/icons folder, icons are in there, you should use the same names. Next version of icon themes module should be made available before April. And then we can turn your work in an icon pack others will be able to use.