After adding support for OS X 10.9 Mavericks in its version 5.0 release, TinkerTool 5.1 from Marcel Bresink is now sandboxed for better security. The under-the-hood customization system utility also does away with the Login Items pane as it’s no longer useful for Mavericks, differentiates between the actual Lucida Grande typeface and the new screen system font introduced with OS X Mavericks, reinstates the preference setting that enables you to copy text displayed by Quick Look (for 10.9.1 and later), and reduces storage space used by the preference reset feature. While the latest version of TinkerTool requires 10.9 Mavericks, Bresink continues to offer older versions of TinkerTool for those running previous big cats, all the way back to 10.1 Puma. (Free, 3.9 MB, release notes)
Option-click to Hide Apps Quickly
This trick has been available in the Mac OS for years, but many people still don't know it. If you have too many windows cluttering up your screen, you can hide specific ones easily as you work. When you're in any application, hold down the Option key and click on another app's window, on the Dock, or in the Finder to switch to that other app and simultaneously hide all the windows in the previously current app.