Mater is a very simple menubar Pomodoro app. It's written in Electron and there are binaries for Mac, Windows, and Linux.
I've used a bunch of Pomodoro apps in the past and never found found one that hit the sweet spot for simplicity and nice design. When I found myself wanting to learn Electron, I decided to scratch both itches at the same time!
Inspired by a Wait But Why blog post, 144blocks is a fun, simple way to visualize where your time is going every day! By breaking down the day into 10 minute blocks of time, you can easily see whether your time is being spent on work, commuting, or doing something you love. Customize and create your own activities to fill your 144 blocks!