TimerLabs - TimerLabs is an interval timer that helps you with your daily routines and session based work
Free Alarm Clock - Free Alarm Clock is a free, full-featured and user-friendly computer alarm clock for Windows.
HIIT (Watch) - A very simple interval timer engineered for Apple Watch
Gnome Clocks - Clock application designed for GNOME 3
Sportos - macOS interval timer that enhances your home workouts
AlarmDJ - Online Alarm Clock - Use YouTube videos or MP3 files as alarm sound. Works offline.