Android: If you constantly switch between running apps, Android's default "Recent Apps" screen probably isn't as nice as you'd like. Task Changer lets you customise how you switch between them as well as which apps show up on the list.
After installing Task Changer, you invoke it by swiping one of a few "zones" on the edges of your phone's screen. By default, they're little coloured blocks, but you can hide those if you'd rather your screen have less clutter. By default, the left zone shows you your recent apps, while the right-hand zone shows you currently running apps -- which can sometimes be an important distinction. You can also add more zones, add your own custom shortcuts to a "favorites" list, and more. Check out the video above to see it in action.
Task Changer is a free download for Android devices. You can upgrade to a Pro version from within the app for a few extra features.