This might be slightly related list, although its not for Gmail, but for Google Groups for G Suite:
 
https://support.google.com/a/answer/6093413?hl=en

> Reserved group names
We reserve certain names that cannot be used if you are creating a group using Google Groups or Google Groups for Business. However, you can use these names if you are creating a group using the Groups control in the Admin console.
>
> abuse  
> admin  
> administrator  
> hostmaster  
> majordomo  
> postmaster  
> root  
> ssl-admin  
> webmaster  

> The names abuse and postmaster are reserved. You can, however, subscribe to them and receive all mail sent to these addresses. (Learn more)