Apple has updated its iOS design resources with a comprehensive set of colors, guides, templates, and UI elements:
Creating iOS apps is even easier with the updated Apple UI Design Resources. Use the latest Sketch and Photoshop templates and guides, color palettes, and the San Francisco typeface to quickly and accurately design iOS apps that integrate seamlessly into the overall user experience of iOS.
The design assets are available to download in both Photoshop and Sketch formats on Apple’s Human Interface Guidelines website. In addition to the new assets, Apple has four videos covering the materials, an overview with User Experience Evangelist, Mike Stern, as well as videos covering design comps, icons, and glyphs, also narrated by Stern.