Mac: We've seen plenty of Pomodoro timers over the years, but Tomates might be the most full featured option around.
If you're unfamiliar, the Pomodoro technique is pretty simple. Set a timer of 25 minutes, work for that duration of time, then take a short break, then reset a timer and work again. It's essentially the Hight Intensity Workout equivalent of productivity techniques. A true Pomodoro timer really doesn't need to be anything more than a short countdown clock, but for anyone who wants a little more, Tomates also works as a lightweight work tracking system.
You can customise work timers in Tomates, set different break times, and even change the alarm sounds. It tracks everything you do, which means you can take a look back out how long you worked throughout the week. There's even a little trophy system if you reach particular goals. It's a pretty simple little app, but it takes it a few steps beyond a standard Pomodoro timer to be something a little more involved. If you're looking for a free timer with less pizazz, check out Pomodoro Time.
Tomates - Time Management ($US2.99 ($4)) [Mac App Store]