if you use Let’s Encrypt (ACME protocol) AFAIK you can find all domains registered in a directory that even has a search, no matter if it’s wildcard or not.

It was something like this https://crt.sh/ but can’t find the site exactly anymore

LE: you can also find some here https://search.censys.io/

While I like his setup, I’m not a big fan of 3D printed components being added to the whole setup primarily because not everyone has a 3D printer lying at home …

The cost though it’s actually quite good I have to say.