Popular stencils
Web Form Elements
Edward Anastas has put together a handy stencil composed of often-used elements in HTML and web page forms: radio buttons, checkboxes, combo boxes, entry fields and text areas. Nice looking and Aqua, to boot.
Apple Hardware Elements 2010
A collection of official Apple hardware icons, for use in physical network diagramming. Includes the following: iMac (all generations) MacBook Pro (unibody, previous generation) MacBook (unibody, previous generation) PowerBook (all generations) AirPort Extreme, Time Capsule Apple Cinema Display iPhone, iPad, iPod Touch XServe...more
Rounded Numbers
Why clutter up your diagrams with a lot of text when the most used way of annotating diagrams is by using a number or a letter inside a circle? Very useful when needing to annotate diagrams, drawings, or photographs.
Round Arrows
A small collection of round arrows to create a circle of arrows. Each arrow can have a different color.
UX People Builder (Guys)
Create your own stylized people for use as personas, icons, individuals, or groups on your charts, diagrams, and illustrations of information, ideas, and concepts. Use in conjunction with UX People Builder (Gals) stencil. Optimal for information architecture, interaction design, and user experience projects.
Web Detail Flowchart
The page title, page file name and page description area labels are editable. I added an example of how I use this stencil. Feel free to use as you like though.
Django Admin
Stencil featuring the out-of-the-box UI elements available when creating admin interfaces for Django sites.
Pretty Urban Building Icons
A collection of icons of urban buildings
OS logos
A collection of OS/hardware logos, including Sun, HP, Linux, Red Hat, FreeBSD, Windows, Debian, Darwin, IBM, and VMware.