LucidChart - LucidChart is the missing link in online productivity suites. LucidChart allows users to create, collaborate on, and publish attractive flowcharts and other diagrams from a web browser.
ServerSuit - ServerSuit is a browser based program that enables remote Linux administration, monitoring, website hosting, and server setup automation.
yEd - yEd is a free desktop application to quickly create, import, edit, and automatically arrange diagrams. It runs on Windows, Mac OS X, and Unix/Linux.
RedGate SQL Monitor - SQL Monitor helps you and your team find issues – before they become problems
textografo - Online diagramming application which generate diagrams based on text and allows real time...
Nagios - Complete monitoring and alerting for servers, switches, applications, and services