The big companies make lots of money using open source, but the projects themselves are always short of time and money. I want to help that by offering free advertising to open source projects. Here is an example for the Jupyter project. The ad is right before the box where you can type a tweet. The Jupyter project ads are on every page of the Jupyter Project branch of the tree.
If you are interested, then please contact me. We can figure out what kind of ad would be best for you.