DisplayFusion - DisplayFusion will make your multi-monitor life much easier.
Evernote - Bring your life's work together in one digital workspace. Evernote is the place to collect inspirational ideas, write meaningful words, and move your important projects forward.
Mizage Divvy - Divvy is an entirely new way of managing your workspace.
Standard Notes - A safe place for your notes, thoughts, and life's work
WindowGrid - Quickly and easily layout windows on a dynamic grid using just the mouse.
Joplin - Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, tagged and modified either from the applications directly or from your own text editor.