Free
Time Out - Break Reminders
A free program for mac
Use This App To Make Sure You Take A Needed Break.
Take A Break, Please is a productivity app that encourages you to, well, take a break. It does this by darkening your screen for a small amount of time on a schedule that you set, for example every 5 minutes on the hour. It works very well and requires minimal configuration, though it provides sparse warnings when your break is upcoming and can't be customized much.
Free
A free program for mac
Paid
Useful Tool for Forgetful People
Paid
Software to Remind PC Users to Take Periodic Breaks
Free
Stay Focused with LookAway Break Reminder
Trial version
Break reminder tool with micro-breaks
Free
Efficient Pomodoro Timer for Mac Users