Social Pomodoro - Meet an accountability buddy for 25 minutes of focused work.
Fliqlo Screensaver - A screensaver that displays the time using a flip clock.
Focusmate - Distraction-free productivity via virtual coworking
Padbury Clock Screensaver - Minimal screensaver for Mac
Habit List - Create good habits and break bad ones with the app that keeps you focused.
Really Slick Screensavers - Really Slick contains free 3D OpenGL screensavers.