It might be so that you have a NetBSD machine, that does not have a monitor connected.
I was abit suprised that it would be a problem. If trying to boot headless, as its called It will panic/not boot.

I thought that i had read somewhere you needed to disable the different graphics drivers
radeon*, i915drmkms* and nouveau* in /boot.conf
Turns out, that is not enough.
Thanks to this thread and rvp's response.
This is what is needed:
/boot.conf

 
userconf=disable radeon*
userconf=disable i915drmkms*
userconf=disable nouveau*
consdev=com0
    

/etc/rc.conf

wscons=NO
    

/etc/ttys
Set all ttyE to off

I am suprised, that it was so difficult to find the answer. I half expected it to be written in boot.cfg(5)
Or that more have struggled with it, to find a blog or such.
Is it obvious, and i am a dummy?
or is it not that common to run NetBSD without a monitor connected?!

Anyway, happy to find a solution.