Popular stencils
Meraki Hardware
Some Meraki Hardware both switches and Firewalls.
Diagramming Reactive Systems
Graphical notation that is used to depict message flows from the Reactive Design Patterns book written by Roland Kuhn with Jamie Allen.
Windows Phone 7 Wireframe v1.0
This is a set of shapes for making wireframes for Windows Phone 7.
Pyramid
Customizable 3D pyramid
SGI icons
Some SGI icons, imported from MaXX Interactive Desktop source SVGs at http://dev.maxxdesktop.com/trac/maxxdesktop/browser
Envelope
A set of colored envelopes that you can use when modeling any messaging application, or anything that requires a message or snail mail. This can also be used to model an outgoing message from a Message Queue or communication between mail servers.
Google Glass Cards
A collection of Google Glass cards and design elements to aid the design process.
AWS Monitoring Icons
AWS Simple Icons for Architecture Diagrams from http://aws.amazon.com/architecture/icons/ converted to stencils.
Opscode Chef
This is a set of Chef stencils for use with OmniGraffle for creating diagrams. This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.