There are a number of databases that list Usenet groups and discussion lists, though none are totally comprehensive. This page lists some of these, and gives a few examples of business-related lists. Business and professional newsgroups. A database of 23,000 lists using the Listserv discussion list management software. Useful feature is that you can specify that you want the list to have web-based archives.
Simple search looks for all the words entered.
Power search allows for more options. This lists 90,000 lists. Mailbase Hosts 2,300 UK discussion lists. In order to be hosted at Mailbase, a list has to have some relevance to higher education. NewList A mailing list that lists new discussion lists, so its searchable archive is a reference source.