If you can't wait for the 2016 Nexus phones from Google to get your hands on some new sounds, it's now possible to download the notification alert sounds as well as the ringtones from the 2016 Nexus devices. Each set has a collection of different tones, although there are more ringtones than there are sounds for the notification alerts. While this may be the latest thing to drop from the upcoming devices which have yet to be announced officially, a set of wallpapers from the Nexus devices this year has leaked fairly recently, and now with the notifications and ringtones in place, you can have the wallpapers and both sets of sounds on your device to somewhat make it feel like you have the new Nexus. Sure, it won't be the same, but it should still be delightful to have some new stuff to customize your phone with.
You can grab the downloads from the buttons below which are both downloadable ZIP files, and after you have those downloaded you'll need to get them onto your device and into the right folder before they can be selected. If you have downloaded the files via your mobile device browser, simply open a file manager app and copy the files from the downloads folder (after you unzip them, of course) into their respective folders where the other ringtones and notification sounds are stored. If you aren't sure which file manager to use or if you don't have one on your device, ES File Explorer works pretty well for this type of task.
Once that's done, you should be able to go into your device settings where you select the tones for each of these and see these pop up. If they aren't there, give the phone a good old fashioned reboot which should force them to cycle into the selection list. The folders you will want to move these files into should be located in the system folder, and then in media, and finally ringtones, or notifications depending on which files you're trying to copy. It's a pretty quick and simple process, even though it may not be as straightforward as using something like the Zedge app which takes care of most of the work, short of finding and downloading the tone you want.