Fellow programmer here. I'm blind myself and would like to thank you for thinking of contributing to assistive technologies. Here's just a few things I thought of:

* $1 - lots of people have mentioned this, it's by far the best open-source screen reader for Windows. You might want to check out $1 in addition to its Github repo and NV Access' Github organisation.
* $1 - this is really the only graphical screen reader for Linux. It primarily targets GTK-based desktop environments and applications, though support is always increasing for electron and QT programs. You might want to check out $1 as well as $1.
* $1 - this is a light-weight Linux magnification tool written in python with GTK.
* $1 - a Linux console screen reader. It's pretty young and is feature-packed, but as with most assistive technologies, could do with more devs.

There are almost certainly more, but those are the main open-source projects I can think of. Of course, contributing to apps and websites to make them more accessible on any platform is also a very good idea.

You might want to check out NVDA $1.

This is kind of... out of the scope of the question, but you might also want to check out ChatMud. It's a mud game built around the concept of you learning how to build objects and generally code, and its filled with programmers.

$1

What are your languagese?

NonVisual Desktop Access (NVDA), one of the most popular screen readers, is open source and always looking for volunteers. Check them out on Github: https://github.com/nvaccess/nvda

I’m not sure if this is what you are looking for, but CS Access for All is a really cool group focused on accessibility on computer science for all people. They may have something they need help with.