Gnome Clocks - Clock application designed for GNOME 3
Workout Timer - A simple, customizable workout timer
Digital Clock 4 - Beautiful customizable clock with plugins
Tabata Timer - Tabata Timer is a mobile application that helps you perform high-intensity workouts.
AlarmDJ - Online Alarm Clock - Use YouTube videos or MP3 files as alarm sound. Works offline.
Stopwatch Timer - Stopwatch Timer is a mobile application that helps you keep track of your time.