Popular stencils
Actifio Icon Set 2012
Actifio Icon Set http://www.actifio.com
Problem Frames Components
Stencil with components for diagramming problem frames.
Flat TV
A simple flat TV
Burndown template
Burndown template for Agile methodology
Fortinet
Stencil for most of the products from Fortinet, including Fortigate, FortiManager, FortiAnalyzer and FortiMail. The Stencil was converted from the official Fortinet Visio stencil.
Formal Network Symbols (Updated)
I use these particular symbols quite frequently, but was always having to clean them up and tweak them. I finally decided to do a complete update to make them more useable. They are now properly grouped, they scale correctly - both stroke and text, and the grouping is proper in the side panel as well.
Solar Panels
Different Generic Solar Panels and form factors Generic MPPT Regulator
Windows 8: Portrait views
Portrait views for Windows 8.
Cisco CVD 2014 LAN Switching Icons and Clouds
Cisco released updated CVD Icons in many formats, but of course, no Omnigraffle stencil. These are built from the PNGs. http://www.cisco.com/c/en/us/solutions/enterprise/design-zone-smart-business-architecture/cvd.html This is the LAN Switching Icons and Clouds section.