This post will go stale very quickly as blocked connectors has only just been released.

This is a list of connectors that I could not block, many I do not want blocked, but there are one or two suprises here.

Note. This is for my MSDN E3 Subscription of O365, your list of The Unblockables may differ.

Those in bold and red are my personal , What the Heck?.

ApprovalsStandardMicrosofthttps://docs.microsoft.com/connectors/approvals
Azure ADStandardMicrosofthttps://docs.microsoft.com/connectors/azuread
Bing MapsStandardMicrosofthttps://docs.microsoft.com/connectors/bingmaps
Bing SearchStandardMicrosofthttps://docs.microsoft.com/connectors/bingsearch
Cloud App SecurityStandardMicrosofthttps://docs.microsoft.com/connectors/cloudappsecurity
Cloud PKI ManagementStandard509 Solutions Pty Ltdhttps://docs.microsoft.com/connectors/cloudpkimanagement
Common Data ServicePremiumMicrosofthttps://docs.microsoft.com/connectors/commondataservice
Common Data Service (current environment)PremiumMicrosofthttps://docs.microsoft.com/connectors/commondataserviceforapps
Content ModeratorStandardMicrosofthttps://docs.microsoft.com/connectors/cognitiveservicescontentmoderator
Custom VisionStandardMicrosofthttps://docs.microsoft.com/connectors/cognitiveservicescustomvision
ExcelStandardMicrosofthttps://docs.microsoft.com/connectors/excel
Excel Online (Business)StandardMicrosofthttps://docs.microsoft.com/connectors/excelonlinebusiness
Excel Online (OneDrive)StandardMicrosofthttps://docs.microsoft.com/connectors/excelonline
Face APIStandardMicrosofthttps://docs.microsoft.com/connectors/faceapi
GitHubStandardMicrosofthttps://docs.microsoft.com/connectors/github
LinkedIn V2StandardMicrosofthttps://docs.microsoft.com/connectors/linkedinv2
LUISStandardMicrosofthttps://docs.microsoft.com/connectors/luis
Microsoft FormsStandardMicrosofthttps://docs.microsoft.com/connectors/microsoftforms
Microsoft Forms ProStandardMicrosofthttps://docs.microsoft.com/connectors/microsoftformspro
Microsoft KaizalaStandardMicrosofthttps://docs.microsoft.com/connectors/kaizala
Microsoft School Data SyncStandardMicrosofthttps://docs.microsoft.com/connectors/microsoftschooldatasync
Microsoft To-Do (Business)StandardMicrosofthttps://docs.microsoft.com/connectors/todo
Microsoft TranslatorStandardMicrosofthttps://docs.microsoft.com/connectors/microsofttranslator
MSN WeatherStandardMicrosofthttps://docs.microsoft.com/connectors/msnweather
NotificationsStandardMicrosofthttps://docs.microsoft.com/connectors/flowpush
Office 365 GroupsStandardMicrosofthttps://docs.microsoft.com/connectors/office365groups
Office 365 OutlookStandardMicrosofthttps://docs.microsoft.com/connectors/office365
Office 365 UsersStandardMicrosofthttps://docs.microsoft.com/connectors/office365users
Office 365 VideoStandardMicrosofthttps://docs.microsoft.com/connectors/office365video
OneDriveStandardMicrosofthttps://docs.microsoft.com/connectors/onedrive
OneDrive for BusinessStandardMicrosofthttps://docs.microsoft.com/connectors/onedriveforbusiness
OneNote (Business)StandardMicrosofthttps://docs.microsoft.com/connectors/onenote
Outlook.comStandardMicrosofthttps://docs.microsoft.com/connectors/outlook
Outlook Customer ManagerStandardMicrosofthttps://docs.microsoft.com/connectors/ocm
Outlook TasksStandardMicrosofthttps://docs.microsoft.com/connectors/outlooktasks
PlannerStandardMicrosofthttps://docs.microsoft.com/connectors/planner
Power Apps for AdminsStandardMicrosofthttps://docs.microsoft.com/connectors/powerappsforadmins
Power Apps for MakersStandardMicrosofthttps://docs.microsoft.com/connectors/powerappsforappmakers
Power Automate for AdminsStandardMicrosofthttps://docs.microsoft.com/connectors/microsoftflowforadmins
Power Automate ManagementStandardMicrosofthttps://docs.microsoft.com/connectors/flowmanagement
Power BIStandardMicrosofthttps://docs.microsoft.com/connectors/powerbi
Power Platform for AdminsStandardMicrosofthttps://docs.microsoft.com/connectors/powerplatformforadmins
Project OnlineStandardMicrosofthttps://docs.microsoft.com/connectors/projectonline
SharePointStandardMicrosofthttps://docs.microsoft.com/connectors/sharepointonline
Skype for Business OnlineStandardMicrosofthttps://docs.microsoft.com/connectors/skypeforbiz
Text AnalyticsStandardMicrosofthttps://docs.microsoft.com/connectors/cognitiveservicestextanalytics
Video Indexer (V2)StandardMicrosofthttps://docs.microsoft.com/connectors/videoindexer-v2
WunderlistStandardMicrosofthttps://docs.microsoft.com/connectors/wunderlist
YammerStandardMicrosofthttps://docs.microsoft.com/connectors/yammer