Users
Sends a notification when a User event is triggered.

When a new user is created
Fires the first time a User is saved. Covers public registrations, admin-created accounts, and programmatic User saves.
When a user is activated
Fires when a User account transitions into the active status. Triggered by email verification, manual admin activation, or re-enabling a suspended User.
When a user is updated
Fires every time an existing User is saved (except activation, see above). Covers profile edits, password changes, and group reassignment.
When a user is assigned to one or more groups
Fires when a User is assigned to one or more groups. Catches programmatic group assignments that bypass a full user save, in addition to admin-driven assignments.
When a user is deleted
Fires when a User account is deleted. Covers both soft deletes (moved to the trash) and hard deletes.
When a user is restored
Fires when a soft-deleted User account is restored from the trash.