Here are some things that aren’t games that might be helpful.

Pomodoro Timer

Check out what a Pomodoro Timer is with this Duck Duck Go search.
You can download mine from these links:

• Linux
• Windows
• Mac (to come)
• Android (to come)

Or feel free to go to the source and build your own / hack it into something different / better. Godot 3.0 code in GDScript.

• Github repository