Vellum is an iOS app for finding amazing looking wallpapers. It has beautiful (and free) hand picked wallpapers for sprucing up your iPhone home-screen. Along with having a great collection, Vellum also has a built in blur tool for creating just the right look. I've tried a bunch of apps like this, and Vellum is the only one I think I will need going forward.

Download Vellum for free on the App Store.