ShuffleTab

By holding control along with the arrow keys, tabs can be arranged quickly and easily within a window, or transferred between them.
Move tabs left or right, group tabs in a new window, and return them to their previous window all without using a mouse!

--- Update 1.50 ------------------------
Added customisation options accessible by clicking on the ShuffleTab logo and going to the Settings tab:
-Decide the behaviour of Control+Down; either moves the active tab,
all until far left, or all until far right.
-Determine if Control+Up returns a tab immediately or if it goes to far
left first.
-Tabs can now remember their position in the previous window; decide
whether you want them to return to it.
and more...