This repo tracks the Application IDs that have been observed in the wild in Azure AD. Application IDs are generated by Azure AD and globally unique. Investigators commonly see these recorded in the Unified Audit Log UserLoggedIn operations to track the application used by the principal as well as the application they are trying to access.
If you know what someone of the unknown IDs map to or have your own to contribute please submit a PR!
Shoutout to @prolsen and https://github.com/prolsen/o365 for great work in enumerating many of these Application IDs!