UI cheat sheet: dropdown field - UX Collective
Icon and Image Sizes (iOS Human Interface Guidelines)
Learn about designing apps for iOS.
Useful Segoe UI Symbols
… compiled list of symbols that can be used to copy Windows 8’s style:
Developing Windows 8 – Using AppBarCommand Icons outside the AppBar « Matt Duffield
One of the things I really like about developing Windows 8 applications is the ability to use the built in icons provided by the Segoe UI Symbol font.
Windows 8 Metro apps – a lot of icons are available out of the box ! | Jonathan ANTOINE's thoughts on WPF, Silverlight, WinRT, NUI...
Windows 8 AppBarIcons enumerated and visualized
Download: http://www.flickr.com/photos/adamkinney/6952800759/
AppControls
… makes it easy to quickly create high-quality custom controls for your iOS apps, Mac apps and for the web.
Apple OS X Lion Buttons in CSS