Advanced Port Scanner - Advanced Port Scanner is a fast and free software for port scanning.
ServerSuit - ServerSuit is a browser based program that enables remote Linux administration, monitoring, website hosting, and server setup automation.
WakeMeOnLan - Turn on computers on your local area network by sending Wake-on-LAN packets.
RedGate SQL Monitor - SQL Monitor helps you and your team find issues – before they become problems
Wake On LAN Ex 2 - Free software from Joseph (AKA BootBlock) of http://www.bootblock.co.uk
Nagios - Complete monitoring and alerting for servers, switches, applications, and services