Although the days of skeuomorphic interfaces are behind us, a well placed texture can still make an app look great. Subtle Patterns is a collection of over 300 free, high quality, tilable textured patterns that are subtle enough that they won't look out of place on iOS 7. Many of the textures are available to download in @2x resolutions as well or the free Photoshop plugin gives you access to the patterns directly in Photoshop.