WindowGrid!

Using Spectacle you can view multiple documents side-by-side, move windows to other displays, or even focus your full attention to a single task.

Aquasnap is a powerful window manager that helps you arrange and organize multiple applications on your desktop with minimum effort. It allows you to achieve maximum multitasking, especially if you own a high-resolution monitor or a multi-monitor setup.

WinSplit Revolution is a small utility which allows you to easily organize your open windows by tiling, resizing and positioning them to make the best use of your desktop real estate.

ShiftIt is an application for OSX that allows you to quickly manipulate window position and size using keyboard shortcuts. It intends to become a full featured window organizer for OSX. It is a complete rewrite of the original ShiftIt by Aravindkumar Rajendiran which is not longer under development.

BetterSnapTool is a utility that mimics Windows 7 Aero snap, allowing you to easily manage your window positions and sizes by either dragging them to one of your screens corners or to the top, left or right side of your screen. This lets you easily maximize your windows or position them side by side.

AltDrag allows you to move and resize windows much easier. When you have it running you can simply hold down the Alt key and then use your mouse to drag any window, and it doesn't matter where in the window you click. This is especially useful in netbooks, with respect to the small screen and touchpad. It simply allows you to do more with less mouse movements.

MaxTo is a small Windows program that divides your monitors into regions. When you maximize a window, it will no longer fit the entire screen, but only the region it was maximized into. Your windows are neatly organized into the grid you have defined when they are maximized. MaxTo has been described as a tiling window manager.

GridMove - A window management tool that can quickly arrange your windows into desktop grids.GridMove is a program that aims at making windows management easier. It helps you with this task by defining a visual grid on your desktop, to which you can easily snap windows. This program comes bundled with some predefined grid templates, that can be easily swaped, but also has ways of creating custom grids or sharing grids made by others.

WinSize2 can move windows automatically to a predefined place and / or resize the width and/or height to a predefined size.If you use different screen resolutions you can store individual window positions for each of the resolutions.

HyperDock adds Windows 7 like features and more to Mac OS X.

Windownaut is versatile window management app that let's you define keyboard shortcuts and active areas on your screen to resize an position the windows on your desktop.

Bluetile is a tiling window manager for Linux, designed to integrate with the GNOME desktop environment. It provides both a traditional, stacking layout mode as well as tiling layouts where windows are arranged to use the entire screen without overlapping. Bluetile tries to make the tiling paradigm easily accessible to users coming from traditional window managers by drawing on known conventions and providing both mouse and keyboard access for all features.