Search by role would be incredibly useful in large servers where members are organized through roles, as the official Discord client only allows admins to see all users with a given role.

You can type @rolename into the filter field and Ripcord will filter to any users already locally cached. Ripcord can't search the server for every possible user with that role, so if you're in a server with more than a few thousand users, it probably won't show the complete list of users with that role.