Be Focused by XWaveSoft - Simple Pomodoro timer in your Mac's menu bar
Hourglass - Hourglass is the most advanced simple countdown timer for Windows.
Social Pomodoro - Meet an accountability buddy for 25 minutes of focused work.
wnr - Better than pomodoro, this timer app balances work and rest.
Time 2 - Stay focused and crush procrastination
Free Countdown Timer - Free Countdown Timer is a free, full-featured and user-friendly countdown timer for Windows