Popular stencils
Napkin UML
Simple hand-drawn UML stencil.
Event-driven Process Chains
Event-driven Process Chains (EPC) are used widely for describing business logic within a company. EPCs have been invented by Prof. Scheer and commercialized by IDS-Scheer: http://www.ids-scheer.com/international/en
Box-and-Arrow Diagrams
The classic elements of box-and-arrow diagrams, widely used in describing Lisp data structures constructed from cons cells.
Events Overview (Magnolia CMS)
Events Overview Paragraphs stencil from the Magnolia CMS Standard Templating Kit (STK) Stencil kit. Events Overview paragraphs make use of the hcalendar microformat.
Simple D&D Map Builder
This is a simple, black and white, stencil for drawing D&D Maps. Create a new document and set it's gridlines on and ensure it is set to 1 inch or 2.54 cm. set gridlines to print. Then, you can drag over the elements of a dungeon. Let me know what you think via my website
Swagger
Swagger is a contract specification for Web APIs that provides a nice way to document them. This Stencil reproduces the compact Swagger style.
Maps
While OmniGraffle probably isn't a tool for professional cartographers, we've found it can be quite useful for making informal maps and directions.
Wireframing stencil
Created by Brian Talbot. For more info, check out www.brian-talbot.com.
Tango Emblems
Tango icon library emblem symbols