Popular stencils
Sun Microsystems: Systems
This stencil contains systems equipment from Sun Microsystems.
Cutting Line
Use this to include cutting lines in your document
Windows Wireframe Stencil
Windows wireframe components from the Windows Stencil Kit.
Windows Phone 7 Wireframe v1.0
This is a set of shapes for making wireframes for Windows Phone 7.
Failure Modes and Effects Analysis
Nice, clean template for FMEA analysis. Beats the usual PowerPoint rendering.
Grammar
Groupings of text and line or arrow items, styled to nicely represent parse trees, syntax trees, or BNF grammar diagrams.
Bayes Elements
Mathematical elements for describing Bayes probabilities. Also includes stencils for sensors and platforms when using these elements for robotics or other applications.
SGI icons
Some SGI icons, imported from MaXX Interactive Desktop source SVGs at http://dev.maxxdesktop.com/trac/maxxdesktop/browser
Generator-Elec
A collection of symbols I put together reworking an Onan generator wiring diagram