First off, let me say how awesome this site is! I've never seen such a complete helpful library of articles for those trying to roll their own OS. Heck, I never even knew making your own OS was a "thing" lol
That said, I too have already added my project to the list.
Mine is Exelyx, a shell-type GUI / application environment which aims to breathe new life into an older PC by bestowing a bevy of modern OS features upon it without weighing it down with uncommonly needed options and fluff.
It has existed since 1995 in one form or another and has pretty much been "that old OS thingy I used to play with" until the last several months, when I sat down and started giving it some serious consideration. The project has almost bit the dust several times, but I can't seem to ever quite close the door on it entirely.
There's not much to see so far, but sometime soon I hope to have basic application running functionality in place. The only obstacles to that now are 1) my LBA direct disk access routines aren't fully finished, 2) the archive / file management subsystem isn't in place yet and 3) there are a bunch of little bugs that need squashed and tweaks that need made.
working correctly so far is: high-res LFB-based VESA graphics with automatic screen mode selection based on resolution and bit depth, a VESA-based system font, string formatting and printing, graphics, animation, pixmap support, basic hardware detection and initialization, minor APM support, CPUID probing and the beginning of PCI bus probing and device detection.
The code is open source so if anyone wants, they can test it out on that old 486 they've been using as a doorstop for the last 15 years
I'd welcome the bug reports from anyone doing so.
Speaking of bugs, there is a rather major known one where the OS boots flawlessly in VirtualBox but hangs on my Compaq Mini's real hardware even though both are running FreeDOS.
That's all for now! I'll announce any major milestones here in the future.