Audit logs that cover user events. Events could include:

login
logout
API key rotation
template change/edit
mailing list change/edit
manual suppressions list add/delete/change
webhooks add/delete/change
sender key creation/rotation
domain add/delete
domain settings (TLS, message retention, tracking settings, etc.)
user role add/delete/change
validations job
IP/IP Pools changes
authentication changes (SAML, Google Auth, etc)
account settings changes (billing details, timeout, downgrade/cancellation)