Android: There are lots of great options out there to help you quickly move between apps without pulling up the app drawer or switching buttons. Slyde wants to make that process even faster by doing away with pull-out drawers and custom interfaces.
You have five bubbles you can customise with apps you want each to launch (or switch to, if the app is already open). Set each one, and then you can activate the app at any time, over any app, by swiping in, over the activation bubble, from the edge of the screen. Continue the gesture to one of the bubbles to go right to that application.
You can customise where that activation bubble fits on the screen, so it can go somewhere your fingers don't usually rest. The video above does a good job of showing you how it works, and how quickly you can use it once you're used to it.
Slyde will set you back $1 if you're interested. Hit the link below to give it a try.
Slyde ($1) [Google Play]