Once you know a list server name, you can sometimes search it for other lists that it also manages.
The best way to find mailing lists is described in how to find mailing lists. However, not all mailing lists are necessarily indexed in the catalogues described there. So if you know of one list server, you can use that knowledge to find all of the lists supported on that server, which sometimes reveals the existence of interesting lists that you can’t find in other ways.
If you know the name of a list server, usually because you are subscribed to a mailing list that it manages, then you can often query the server directly with a “lists” request. This command will usually cause the server to return a message which describes all of the mailing lists supported by that list server. Simply send the list server address (not an actual list address) an email with the following command in the body of the message: