Network stencils
OS logos
A collection of OS/hardware logos, including Sun, HP, Linux, Red Hat, FreeBSD, Windows, Debian, Darwin, IBM, and VMware.
Isometric icons
A handy set of isometric icons based on Visio's icons.
Apple Elements
Stencil of additional Apple hardware and misc. networking components. Excellent for creating physical diagrams.
QLogic Switches
Stencils for QLogic Fibre Switches
Cisco Stencils (Wireless)
WLANs, RF, etc.
HP9000
The first palette in the series contains the following stencils: - HP9000 N Class Front View - HP9000 N Class Rear View - HP9000 L Class Front View - HP9000 L Class Rear View - HP9000 V Class Front View (with shadow) - HP E-41 Rack Unit (Empty) - HP E-41 Rack Unit (With 4 N Class Front View) - HP E-41 Rack Unit (With 4 L...more
Cisco Stencils (Voice)
Voice, VoIP and other related devices.
Cisco Stencils (Services)
Group of conceptual and functional icons.
Network 3D
The following picture shows an OmniGraffle palette I put together for doing network diagrams. It may be useful for others.