You may use these materials without restriction to facilitate your app design and implementation.
Phone & Tablet Stencils
Drag and drop your way to beautifully designed Android apps. The stencils feature the rich typography, colors, interactive controls, and icons found throughout Android, along with phone and tablet outlines to frame your creations. Source files for icons and controls are also available.
Action Bar Icon Pack
Action bar icons are graphic buttons that represent the most important actions people can take within your app. More on Action Bar Iconography
The download package includes icons that are scaled for various screen densities and suitable for use with the Holo Light and Holo Dark themes. The package also includes unstyled icons that you can modify to match your theme, plus source files.
Android Wear Materials
The toolkit contains detailed specs and measurements of all of the primary Android Wear UI components. Available in PDF and Illustrator formats.
Sample user flow patterns
Examples of how to chain together simple Android Wear UI components into common user flow patterns, from simple notifications to complex interactions involving full screen activities.
Sample app design mocks
Stream cards and UI elements for some example apps in fully editable PSD format.
Ice Cream Sandwich introduced a new type family named Roboto, created specifically for the requirements of UI and high-resolution screens.
For Android Wear, Roboto Condensed is the system font and the Regular and Light variants should be used by all Wear apps.