Though most of my work is proprietary, I do occasionally make little tools to make my life easier, or to explore a new codebase.
Checking pip requirements files can be a drag, so I decided to make an app that not only checks to see which of your requirements is out of date, but how out of date they are.
I participate in quite a few video calls, both for work and for teaching, so I created a simple page for when the class is breaking until a certain time, or I'm away from my desk, and will be back in a minute.
I occasionally run a Pathfinder game, and sometimes I throw together a script to help things run more smoothly, from rolling dice for me (sacrilege!) or helping run through randomized events.