For a couple years now, I have been using an app called SwipePad on all of my android devices. This app allows you to launch apps with a quick swipe from the edge of the screen. You choose a swiping "Hot spot" (location for the gesture to begin), determine which apps should appear there, and viola! You can either set specific apps to appear, or you can have it set to recently opened apps. The app is free, but there are a couple of bonus add-ons for $1 each. I personally only purchased the dynamic pad add-on, which lets you change the amount of apps that appear when you swipe.
Now, I know that this is a really popular app already, and im sure most of you have heard about it before. There are 2 reasons i bring it up though. For those who dont know about it, this app is INCREDIBLY handy, especially on a bigger device like the Z Ultra.
The second, and in my opinion more important reason, is that swipepad has introduced a theming engine for this already awesome app. I just so happened to stumble upon some themes made by dev FlyingRhinoCMG. I also happened upon his Google+ community for swipepad themes. He does AMAZING work. Not only that, but he takes requests. I asked him for a Super Mario theme as perhaps an idea, and he had one made by the time i got home from work the same day. He only charges a buck for the themes, and they are well worth it. If you havent used swipepad, or you have but wanna spice it up, please take a moment to check both out. Links Below.
SwipePad - https://play.google.com/store/apps/d...ipepad.android
SwipePad Themes - https://play.google.com/store/apps/d...FlyingRhinoCMG
Theme Community on Google+ - https://plus.google.com/u/0/communit...77419262658145
TL;DR? Click these links, try these apps. Cheers!