Guake is a drop-down terminal application in GNOME. Installing Guake is easy. Use your distribution’s package manager, most distros have it in their repositories. In Arch, I just
$pacman -S guake [enter]
You can configure Guake to follow your theme and also change the hotkeys. The example above has transparency and added in the startup application list.
You can just as well use the Cntrl+Shift+T shortcut to get Gnome-terminal but when you need to open many instances of the terminal to do jobs simultaneously, Guake is convenient and clean because in one click of the key it drops down and keep tabs.