Yahoo Stencil Kit

Yahoo has released its "Stencil Kit" as a part of Design Pattern Library. This seems to be a great idea and very useful resource to the designers. Though this may lead to yahoo biased design ideas, the standard approach to components can be a welcome idea. The stencil kit has following topics:
• Ad Units
• Calendars
• Carousels
• Charts and Tables
• UI Controls
• Form Elements
• Grids
• Menus and Buttons
• Mobile - General
• Mobile - iPhone
• Navigation and Pagination
• OS Elements
• Placeholder Text
• Screen Resolutions
• Tabs
• Windows and Containers

These are available for download in various formats (OmniGraffle, Visio (XML), PDF, PNG, SVG)
Link: Yahoo Stencil Kit