SleepBot - SleepBot is a sleep tracking app available in Google Play and the Apple App Store.
Free Alarm Clock - Free Alarm Clock is a free, full-featured and user-friendly computer alarm clock for Windows.
KClock Clock - Universal clock application for desktop and mobile Linux
Gnome Clocks - Clock application designed for GNOME 3
Clock You - Privacy focused clock app built with MD3
Sleep as Android - Common alarm clocks ignore your sleep cycles, they wake you on schedule no matter your are currently in your deep sleep. Waking up from deep sleep is unpleasant, it makes you tired and it may negatively affect your productivity during the whole day.