Pomodoro Timer
A simple time management tool applying the Pomodoro (Italian: tomato) Technique, labeled thus in the 1980's by Francesco Cirillo, then a university student. It is named after a tomato-shaped kitchen timer.
Specify a task to work on and start the timer. A floating timer appears. After each countdown, a circle appears behind the respective item in your list, enabling you to keep track of how much time ("how many pomodoros") you spent on each task. The program allows you to view tasks from previous days and add these to your current task list. Double click on a task to mark it as completed. Basic statistics can be displayed to boost productivity.
Though only Windows binaries are released, it should technically work cross platform (haven't tried). The initial program was created mostly by LLM in a matter of minutes.
A complete tutorial for using the technique written by Cirillo can be found at:
https://friend.ucsd.edu/reasonableexpectations/downloads/Cirillo%20--%20Pomodoro%20Technique.pdf