Check out this overview of the most commonly used Microsoft 365 portals

In this blog, an overview of the most commonly used admin center URLs of Microsoft 365, Azure, SecurityCenter.
Office 365 Suite
Office 365 Suite: https://portal.office.com
Outlook Online: https://outlook.office.com
Projects: https://project.microsoft.com
Office 365 admin
Microsoft 365 Admin Center: admin.microsoft.com or https://aka.ms/admincenter
Azure AD https://aad.portal.azure.com
Admin Teams https://admin.teams.microsoft.com
OneDrive https://admin.onedrive.com
Store for business https://businessstore.microsoft.com
Exchange
Exchange Online (old) Https://outlook.office.com/ECP
Exchange online (new) https://admin.exchange.microsoft.com/
Device management
Endpoint manager http://devicemanagement.microsoft.com/ or https://endpoint.microsoft.com
Endpoint manager for education/education https://intuneeducation.portal.azure.com/
Security & Compliance
Cloud App Security portal https://portal.cloudappsecurity.com/
Compliance portal https://compliance.microsoft.com
SecureScore portal https://securescore.microsoft.com
Security Center https://securitycenter.windows.com
Azure ATP: https://portal.atp.azure.com
Microsoft Azure
Microsoft Azure: https://portal.azure.com
Azure AD: https://portal.azure.com/#blade/Microsoft_AAD_IAM/
Microsoft OneDrive
OneDrive admin center: https://admin.onedrive.com/
Microsoft Teams
Microsoft Call Quality Dashboard https://cqd.teams.microsoft.com
Microsoft Teams Admin Center https://admin.teams.microsoft.com
Microsoft Teams Rooms Managed Services https://portal.rooms.microsoft.com
Other
MFA Setup: https://aka.ms/mfasetup
Can't find a portal?
There are several direct links not published to focus on the biggest and most important ones. If you have another portal that you use often, comment at the bottom of this article and we will put it in this list.
Also view
Cmd.MS is a convenient place to quickly navigate to all Microsoft portals.
[Cmd.MS] The Microsoft Cloud Command Line

Thanks Jasper, I have three other URLs that have "all" portals on them for you and your readers:
https://moap.ms/
https://msportals.io/?search=
https://msadmin.center/
how can i retrieve undeleted old mails,or recall them back in outlook, i can only go on until 2015 all older mails seem to have disappeared?