I've been involved in building open source software since the early 90s. Unfortunately I can't find links for some of them, but here are ones for which I do. The most recent ones are at the top.
Humbug
Humbug is an operating system for human/AI collaboration.
Menai
Menai is a compiled, pure functional programming language designed specifically for AI use, featuring an optimizing compiler and infinite-register virtual machine. Being side-effect-free, the language is designed to be safe for AIs to use without requiring user authorizations. Its functional design also makes it ideal for composing complex operations out of simpler ones; a common pattern in AI use.
The language was originally called AIFPL (AI Functional Programming Language)
Metaphor
Metaphor is an AI prompt creation language.
siterender
Have ChatGPT write a pre-rendering tool for websites!
countdown
Find solutions to the "Countdown" numbers game as quickly as possible.
c8
A high performance arbitrary precision natural numbers, integers, and rational numbers library written in "modern" C++.
gcc (Ubicom processor backends)
gcc backends for Ubicom's IP2k and Ubicom32 processor families.
Liquorice
A very small operating system and IPv4 network stack, written entirely from scratch. It was designed to run on 8-bit Atmel AVR and 32-bit x86 processors.
VSTa
A self-hosting microkernel operating system built in the 1990s.
mkdosfs
The Linux mkdosfs command.