Tab Reorder от Glin

Tab Reorder is a Firefox addon that help you move the active tab to the left or right directions via toolbar button or keyboard shortcut.

When you install the addon, default moving direction is left. Simply click on the toolbar button to move the active tab to the left direction. Besides, you can use (Alt + Shift + A) key combination to reorder tabs. If you need to reverse the moving direction, please open addon options page and mark the reverse direction setting (setting number 2). There is also a setting in the options page to exclude - pinned tabs - from moving.

Note: in order to report bugs, please fill the bug report form in the addon's homepage.