Trying to find a source of icons for use within internal documentation for M365 suite

I create internal org-specific documentation on M365 applications.
Quite often I need icons. not just of the apps, but of icons used inside the apps, e.g. the icons on the left-hand rail in MS Teams.
I have accessed the Branding Kit on the FastTrack Portal but that appears to only contain official icons of the apps and in assorted sizes.  These are very useful, but I was hoping there would be a store of icons used all over and within M365.  I realise that a collection of such icons could run into tens of thousands, but I work on the basis that if you don't ask you don't get.

Can anyone help me?