XNote Stopwatch - Try the most feature-rich stopwatch and timer software on the net for free!
TimeLeft - TimeLeft is a versatile desktop utility - it can be used as a countdown clock, reminder, clock...
Hourglass - Hourglass is the most advanced simple countdown timer for Windows.
Stopwatch - A Java countdown timer and stopwatch. Features a fullscreen and a resizable window mode.
Dial - Quick & beautiful macOS timer.
wnr - Better than pomodoro, this timer app balances work and rest.