As you all know, the Android L Developer Preview is now available for Nexus 5 and Nexus 7 2013 (Wi-Fi version) devices. Though there is no official information as to when the stable Android L (Android 5.0) will roll out, the developer community has started their work to make the features available on it for other Android devices.
You can now download wallpapers and ringtones present in Android L developer preview and use them on any of your Android phone. While wallpapers comprise 11 high-resolution images, including the signature wallpaper, ringtones and alarm tones includes some nice tones.
Note: if you do not know how to apply these wallpapers properly (without cropping) on your Android phone, install a free app called “Image2wallpaper” from Play Store. It lets you sets the picture as wallpaper with or without resizing (source).