Uselessd in its early stages of development is systemd reduced to being a basic init daemon process with "the superfluous stuff cut out". Among the items removed are removing of journald, libudev, udevd, and superfluous unit types.
Uselessd meanwhile adds in support for compiling it under musl and uClibc as alternatives to using glibc. Uselessd is also in the early stages of being ported over to FreeBSD while upstream systemd only cares about Linux compatibility.
It's not clear how the init wars will end and if uselessd will end up generating a following or extra developers, but those wishing to learn more about this serious project (contrary to its name) can visit the new project site.