apt-howdy notifies when new packages are available for their installation.

apt-howdy is a tool that helps to track new debian packages available in
repositories. It is intended to work with environments where new packages are
added to repositories every now and them.

It creates a RSS page where it adds new packages added to repositories after
doing an update (default is /var/lib/apt-howdy/new-packages.xml).

You need to use your favourite RSS reader, point to that page, and you will be
notified about those new packages.