I have been trying to iterate through items under a document lib and a folder under a document lib in Sharepoint using Microsoft Graph API V1.0 and Beta too.
I can list doc lib using following request:
https://graph.microsoft.com/v1.0/sites/mysite.sharepoint.com:/FOA/BD:/drives
but I can't iterate through items under a specific drive under above path.
After a long research I tried with beta all the way to list all items under a drive still no result:
https://graph.microsoft.com/beta/sites/mysite.sharepoint.com:/foa/bd:/lists/Budget/
I followed Get an item in a list, but still no success.
https://graph.microsoft.com/v1.0/sites/mysite.sharepoint.com:/FOA/BD:/drives/{drive-id}/root/children
Is that what you're doing? Are you getting an error when trying this? – Ryan Gregg