A long time ago, we asked our intern to develop a time tracker as a CLI, given that we spend most of our time in the terminal and also to give him something fun to do. He designed a great time tracker that we now use daily: Watson (https://github.com/TailorDev/Watson).
Our business involves billing clients per days (7h a day). Watson was our source of truth but sometimes we needed to aggregate reports of different developers. Crick (https://github.com/TailorDev/crick) to the rescue!
These open source tools were part of a much bigger project that never took off. Watson was open source per se but we thought we could maybe create Crick as a paying-product. We conducted interviews and decided not to do that: nobody really needed such a tool. Well. We needed it so we developed it and decided to open source it.