MDriven GraphAPI Sharepoint Document Access
Its really useful when you build a detailed information system to be able to tie in document links from your office365 sharepoint site. These links - that are based on DriveId and ItemId are kept and unbroken even when users rename folders and move documents around in sharepoint.
Your system can then act on these links in any way you see fit.
This is an alternative to using meta data tagging in sharepoint (that everyone hates) - instead you do a large coherent meta-data-system and tie documents to it!