This plugin allows you to alert on down hosts and the breaching of values in your graphs.

This is a few simple Network Tools that you can use from within Cacti. Currently allowes a few web service checks, and SNMP Walking.

This plugin displays information about all the current plugins, and checks for updates.

Weathermap is a network visualisation tool, to take data you already have and show you an overview of your network in map form.
Support is built in for RRD, MRTG (RRD and old log-format), and tab-delimited text files. Other sources are via plugins or external scripts.

Check_mk plugin for cifs monitoring on Linux

ntopng is a web-based network traffic monitoring application released under GPLv3.
It is the new incarnation of the original ntop written in 1998, and now revamped
in terms of performance, usability, and features.

Coppermine is a multi-purpose fully-featured and integrated web picture gallery script written in PHP using GD or ImageMagick as image library with a MySQL backend.

Open source content management platform

Drupal is a free software package that allows an individual or a community of users to easily publish, manage and organize a wide variety of content on a website. Tens of thousands of people and organizations have used Drupal to power scores of different web sites, including

* Community web portals
* Discussion sites
* Corporate web sites
* Intranet applications
* Personal web sites or blogs
* Aficionado sites
* E-commerce applications
* Resource directories
* Social Networking sites

FusionDirectory is a combination of system-administrator and end-user web
interface, designed to handle LDAP based setups.

Provided is access to posix, shadow, samba, proxy, fax, and Kerberos
accounts. It is able to manage the Postfix/Cyrus server combination
and can write user adapted sieve scripts.

Eagle Mode is an advanced solution for a futuristic style of man-machine communication, in which the user can visit almost everything simply by zooming in. It has a professional file manager, file viewers and players for most of the common file types, a chess game, a 3D mines game, a multi-function clock and some fractal fun, all integrated in a virtual cosmos. Besides, that cosmos also provides a Linux kernel configurator in form of a kernel patch.

By featuring a separate popup-zoomed control view, help texts in the things they are describing, editable bookmarks, multiple input methods, fast anti-aliased graphics, a virtually unlimited depth of panel tree, and by its portable C++ API, Eagle Mode aims to be a cutting edge of zoomable user interfaces.