Digital Clock 4 - Beautiful customizable clock with plugins
Gnome Clocks - Clock application designed for GNOME 3
Free Alarm Clock - Free Alarm Clock is a free, full-featured and user-friendly computer alarm clock for Windows.
AlarmDJ - Online Alarm Clock - Use YouTube videos or MP3 files as alarm sound. Works offline.
KTeaTime - KTeaTime is a handy timer for steeping tea. No longer will you have to guess at how long it takes for your tea to be ready. Simply select the type of tea you have, and it will alert you when the tea is ready to drink.
Clock + - Alarm clock, timer, and stopwatch application for Android