You’re asking if someone can give you the names of any telemetry endpoints that may exist in the future?

If you’re that worried about it and suspect Mozilla will act maliciously then you should probably use a different browser/fork. Since pihole blocking depends on the browser respecting your system DNS.

If they were trying to be malicious they could resolve DNS through a custom module over an encrypted connection. Pihole doesn’t block DNS, it simply filters the DNS queries issued by your system. Malicious apps can still resolve DNS queries without using your system’s DNS which will completely bypass pihole.