Hourglass - Hourglass is the most advanced simple countdown timer for Windows.
Unity - The multiplatform game creation tools for everyone.
Online Alarm Kur - Free online alarm clock, set alarm easily on your computer using the internet alarm clock without downloading any software, wake up in time with the loud online alarm clock.
Godot Engine - Feature-packed 2D and 3D open source game engine.
KukuKlok - Kukuklok is a free alarm clock available online and offline.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.