Hiya! I'm still looking for help with the NetBSD image. It's almost
working, but I lack the NetBSD expertise or the time to address the last
few issues. If you're interested in NetBSD support for builds.sr.ht,
please pull down the builds.sr.ht tree and build the NetBSD image:

https://git.sr.ht/~sircmpwn/builds.sr.ht

Use the images/netbsd/8.x/genimg script to generate an image. I have a
pre-generated image available here:

https://yukari.sr.ht/netbsd.qcow2.xz

The only outstanding issue is resizing the partition and filesystem to
use all available space on the disk, either on first boot or as part of
the genimg process. Without this, the images cannot bootstrap
themselves, which is an acceptance criteria for bringing on NetBSD
support.

Please take a look and send a patch if you can get it working! I have
tried to work on this myself but it's out of my wheelhouse and I can't
sink more time into it.