What Window Management Options exist for OS X?

I'd like to do **something** with my windows on OS X, where **something** includes options like re-arranging, moving, re-sizing, remembering positions, cloning across Spaces, etc. What options exist? ### Rules - **One** app per answer. - Use this format for the first two lines of your answer: **## [app name](link to website)** **[App Store](link to appstore) (price)** - **Check for duplicates** before adding new answers. - If you find a duplicate, vote it down and encourage its poster to upvote the original entry instead (and remove the dupe). - Include short **description** about what this Window Managing app does. - What makes this Window Manager app different than the others? - Is it focused on re-sizing using only the keyboard? - Is it focused on moving using only mouse gestures? - Etc.