Populating AD fields and synchronizing them to AzureAD has come up on a couple projects in as many weeks. So mostly for my future reference: here’s the list of fields that are synchronized to AzureAD with the Azure AD Connect tool.

https://social.technet.microsoft.com/wiki/contents/articles/19901.dirsync-list-of-attributes-that-are-synced-by-the-azure-active-directory-sync-tool.aspx