Microsoft 365 admin center
https://admin.microsoft.com or https://portal.office.com/adminportal/home or https://aka.ms/admincenter
Microsoft Purview compliance portal (FKA compliance center)
https://compliance.microsoft.com (this is the one portal that needs a search link the most, so doesn't have one)
Microsoft Purview preview portal
https://purview.microsoft.com
Microsoft Purview governance portal
https://web.purview.azure.com
Microsoft Entra admin center
https://entra.microsoft.com
(the old Azure AD Admin Portal, https://aad.portal.azure.com, redirects to here)
Microsoft 365 Defender (FKA security center)
https://defender.microsoft.com or https://security.microsoft.com
(the old Security & Compliance Center, https://securitycenter.windows.com/, redirects to here)
Office 365 Security & Compliance
https://protection.office.com
(now superseded)
Microsoft Defender for Cloud Apps (FKA Microsoft Cloud App Security) admin center
https://portal.cloudappsecurity.com/
(planned to be superseded by the Defender admin center)
Intune Admin Center (FKA Microsoft Endpoint Manager admin center FKA Intune)
https://intune.microsoft.com or https://endpoint.microsoft.com or https://aka.ms/in
Exchange admin center
https://admin.exchange.microsoft.com
Classic Exchange admin center
https://outlook.office365.com/ecp
SharePoint admin center
https://admin.microsoft.com/sharepoint or https://<TenantName>-admin.sharepoint.com
Teams admin center
https://admin.teams.microsoft.com
Azure Cloud Shell
https://shell.azure.com