gnus-notify.el is a mode that display gnus news number at mode-line. Combined with GnusDemon, it warns you when you receive new mails or when there are new news to read. Clicking the modeline brings you to corresponding summary buffer.
There are several alternatives, see GnusNotificationComparison.
gnus-notify allows you to select which groups you want to include in the report; it does this via a „group parameter“ you have to add manually.
To do it: use
G p in the group buffer, then add
(modeline-notify t) to the list there; if it were the only property, it would look like this: