I've been meaning to try Gobo for a while. I didn't realize it was that out of date! Glad it's being maintained. Slackware was my first distro and it hasn't seen a release in a while.
What other good non-systemd distros are there? Currently I run Gentoo on my main box, and a mix of Void or Alpine on various servers. It seems to be more and more difficult to find good distros that doing depend on systemd.
It's still pretty useful for caching. I have 128GB on one box and I still setup a swap partition. The kernel will make full use of it if you allocate it.
the ones you named are the main ones.
If you are looking for something outside of gentoo. Void is my choice, behind gentoo. It's actually using euvdev, instead of udev, which gentoo doesn't even do at this point.
And it has something particularly interesting to me. An actual alternative to elogind. Turnstyle. It looks like it's still being worked on, but it works now. Besides not just being a gutted systemd programs, I really like it because it's a more unix way of doing session management. Turnstyle handles variables like the runtimedir, and then seatd takes care of seat management for it. Also it works perfectly with runit. And you can add user services, like one for dbus, that starts with your graphical session. So you don't have to use a wrapper to launch it.
That, and void just works like arch generally. Has the xbps-src repo, the package manager is actually pretty decent, even if the I kind of hate the way things are named with it. Also something I've done, is added the extra packages I don't want into the /etc/xbps.d/ignore.conf file. Ones like elogind pipewire pulseaudio., along with stuff like firmware I don't need. So you can avoid them getting pulled in as dependencies. Though you end up having to find some ways around some packages, that need the the ignored packages.
There are also the non-systemd forks for other distros. I can't really speak much on those.