Similar to JorgeCarvalho's suggestion to allow SharePoint mailboxes to be targeted by the Office 365 Outlook integration (https://powerusers.microsoft.com/t5/Flow-Ideas/Flow-to-support-SPO-Site-Mailbox/idi-p/5982)
It would be supremely useful if we could select shared mailboxes too (and even resource mailboxes too) for Flows. At the moment, personal credentials are chosen (shared mailboxes don't have authenticable accounts).
You can now both trigger on shared mailboxes and send mail from shared mailboxes. Read more here: https://flow.microsoft.com/blog/canada-mailboxes-aad/
I also need Flow to work with a Shared Mailbox in O365.
Would be great to be able to have a "Move message to shared mailbox" action too.