Looking at the options on
nosystemd.org,
Finit seemed interesting.
It's been around for a while - started in Dec 2007 as a reimplmentation of Asus's proprietary "fastinit", it originally focussed on embedded systems but now the website states "
Finit is capable of running on both desktop/server systems with udev and embedded systems that usually come with BusyBox mdev", and it has specific
examples for Alpine, Debian, and Void, but I'm not finding any coverage of people using it. :/
Searching LQ, there was a Slackware thread last year, but apparently the only interest was from Inxi's author:
https://www.linuxquestions.org/questions/slackware-14/anyone-tried-finit-aka-fast-init-on-slackware-4175713703
The package has migrated from Sid (unstable) to
Bookworm (testing) at some point (and is in
Ubuntu 22.04 onwards), but there's no backport available.
So yeah, has anyone tried it? (Either on Debian/derivatives or any others.)