Splashtop Wired XDisplay!

spacedesk is a windows network display monitor software that expands the Windows desktop computer screen to other computers over the local area network.

Duet makes your iPad and your Mac more powerful together. Slide Mac apps to your iPad as a second display. No lag, Duet helps you multi-task and work faster with more screen space. It doesn't require internet, just plug and play to get started and you can use the iPad's touch display too. Draw on the screen, produce beats with midi boards, design on the iPad and more.

Turn your iPad/iPhone or Android tablet or smartphone into a convenient side monitor for your Windows or Mac desktop. iDisplay is a universal app specially optimized for iPad, iPhone, iPod Touch, and Android devices screens.

Use your iPad as a wireless display, to extend your computer desktop. Ever wish you had an extra display for your computer? There’s an app for that! With Air Display, you can use your iPad as an additional monitor for your Mac OS X or Windows computer. You can connect via USB (for the best speed and reliability) or Wi-Fi (if you want to walk around with your tablet).

Smart devices become monitors by connecting them to a PC via USB! The Convenient Connect TwomonUSB

DisplayPad is a cutting edge app that allows you to use your iPhone as a second display for your Mac. You can extend your desktop with a wireless display that you can carry around with you!