Python

Python niche: 

https://www.portabledevapps.net/jupyter-portable.php

https://www.portabledevapps.net/python-portable.php

https://sourceforge.net/projects/portable-python/files/Portable%20Python%203.10/

https://www.pythonanywhere.com/

http://winpython.github.io/

POP3 C# goodies:

https://csharp.hotexamples.com/examples/-/Pop3Client/-/php-pop3client-class-examples.html

Windows 10 & 11 Sound Keyboard Application free download

The Linux niche:

The best Linux distro for old computers - Spanish Paradise:

https://loc-os.sourceforge.io/descargas.html

The Uber Ultra Super Linux ever:

NuTyX the swiss king:

http://www.nutyx.org/en/

https://www.joberty.rs/

https://www.helloworld.rs/oglasi-za-posao/programiranje

https://poslovi.infostud.com/

https://www.iwolm.com/en/technique-of-swish/