First we have ReachApp, which is still in beta. We've been using it for a few days now and haven't run into too many issues. ReachApp brings true split-screen multitasking to the iPhone by placing the last used app in the Reachability view. Users can also choose to place the notification center in the view instead of an app. There's also the option to resize the Reachability view.
ReachApp is free, but you have to add the beta repo in Cydia (http://elijahandandrew.com/repo/) in order to use it.
Next up is Switchability, a new iOS 8 tweak for your jailbroken device that brings the multitasking app switcher to Reachability. With Switchability, you can simply double tap (not press) the home button and view your multitasking switcher in both a 3d/2d layout, along with the original app you were running.
Switchability is multitasking switcher combined with reachability. Initially includes a 3d and 2d layout, reachability size slider, favorite app button (+), delete button (x), and more. Updating with new layouts and features based on your requests. iPhone 6 and iPhone 6 Plus compatible (more devices coming soon).
Switchability is available for $1.99 in Cydia for iOS 8+ devices.
Remember that Reachability is limited to the iPhone 6 and iPhone 6 Plus; however, you can install the ReachAll tweak from Cydia to enable Reachability on older devices.
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