DisplayFusion - DisplayFusion will make your multi-monitor life much easier.
altdrag - AltDrag allows you to move and resize windows much easier.
Ultramon - UltraMon is a piece of software built to help with the management of multiple screens on the same computer system. Without software like this, taking full advantage of an expanded desktop space can be difficult.
WindowGrid - Quickly and easily layout windows on a dynamic grid using just the mouse.
Actual Multiple Monitors - Actual Multiple Monitors is a software utility which offers the comprehensive solution to improve the functionality of Windows user interface for comfortable and effective work with multi-monitor configurations.
AquaSnap - Too many windows on your screen? Stop wasting your productivity.