PyScripter, an Open Source, freely available Python IDE written in Delphi, has reached 1 million downloads from Sourceforge. This is in addition to many millions of downloads from its earlier home at the now defunct Google Code and an unknown number of downloads from other distribution channels.
Historic note:
The initial motivation was to build a good scripting solution for Delphi applications. About 20 years ago Microsoft was still promoting ActiveX scripting and Windows Script Engines (such as vbScript and jScript) as the way of building scripting solutions for Windows applications (one of many Microsoft technologies that was all but abandoned). At that time Python was relatively unknown, but it so happened that it was available as a Windows Script Engine and I looked into it. I loved the clean syntax, the expressiveness and conciseness of the language. Other things I liked were duck typing, batteries included, strong object orientation (everything is an object) etc.. The first iteration was an IDE (editor/debugger) for ActiveX Script Engines. But there were many bugs and limitations of Active Scripting both on the Microsoft/Windows side and the Python side.
I then came across Python4Delphi which at the time was maintained by a Canadian developer Morgan Martinet. I started contributing to that project and later become its main maintainer, when Morgan's interested shifted to other things. I also developed a simple Python IDE which was named PyScripter and was originally distributed alongside Python4Delphi. There was very few Python IDEs available at the time and somehow the project became known in the Python community and instantly popular. For me, developing PyScripter was just a hobby, but I received a lot of encouragement and kept on improving it. I was also making some income from donations and Google AdSense. Both PyScripter and Python4Delphi were later moved to Google Code. Python popularity was steadily increasing and at the peak of PyScripter's popularity around 2010, there were hundreds of thousands of downloads the days following each new release.
More recently as we all know Python became one of the most popular programming languages, but at the same time there was strong competition to PyScripter from freely available commercial grade IDE's such as Jetbrains PyCharm and Microsoft's Visual Studio and Visual Studio Code. PyScripter was almost abandoned when Google Code closed down due to my frustration, but after a couple of years of inactivity the project was moved to Github and development resumed. Downloads are available through Sourceforge, since 2016. Through the years PyScripter has kept a large and loyal group of followers. I get many comments along the lines "I have tried VSCode, I have tried PyCharm, but I keep going back to PyScripter". PyScripter is also quite widely used in many Universities for introducing Python to students.
And almost 20 years after its first release, PyScripter is still going strong...