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.
Dial - Quick & beautiful macOS timer.
SnapTimer - SnapTimer is a simple, free, portable countdown timer for Windows.
DS Clock - Keep your time synchronized with Atomic Time servers, using customizable digital desktop clock with westminster chimes.
Be Focused by XWaveSoft - Simple Pomodoro timer in your Mac's menu bar