I know about things like https://crt.sh but how could you be notified about something like this? Is there some service that allows you to be alerted whenever a new certificate is generated for a domain?
"Certificate Transparencyis an open framework which helps log, audit and monitor publicly-trusted TLS certificates on the Internet. This tool lets you search for certificates issued for a given domain and subscribe to notifications from Facebook regarding new certificates and potential phishing attacks."
most commercial offerings are about monitoring your own domain, e.g. from cloudflare, sslmate, etc.