Microsoft 365's Core eDiscovery tool allows litigation holds to be placed on Outlook mailboxes; SharePoint; OneDrive; and Teams accounts. You can avoid adding the URL of each OneDrive site, and adding mailboxes one by one, by making use of a PowerShell script posted on the Core eDiscovery reference guide here. For a selected domain, the script can use email addresses to locate mailboxes. Up to 1000 different email addresses can be used.
The script prompts the admin to enter a search query. The hold can be limited to data that meets particular search criteria.
It's necessary to create a text file with a list of email addresses the script will process.
The script generates logs of the locations of mailboxes and OneDrive sites that are on hold and are not on hold.