Popular stencils
AIGA Symbol Signs
Used at airports and transportation hubs, the AIGA symbol signs are a joint effort between AIGA and the U.S. Department of Transportation. Especially nifty for making maps of floor layouts for public display.
Braces
Braces in different thickness and size.
Vmware Icon Library
Diagram and Icon Library
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.
Round Arrows
A small collection of round arrows to create a circle of arrows. Each arrow can have a different color.
Tabs
Tabs stencil from the Design Stencil kit in the Yahoo! Design Pattern Library.
iPhone / Color Stencil
All new elements for iOS7 flat style. You can change colors to fit your requirements. It's fresh, cool and yet useful!
Annotations
A set of annotations for photographs and diagrams inspired by the excellent annotations available in Little Snapper from RealMac Software.
Bantik UML
Because UML doesn't have to be black and white... Version 2 turns the 'object' object into a table, making adding an attribute, method, or private method as simple as command-enter.