Behodar:

 

My gut feeling is that at present CGN is still a relative rarity, so a list of providers that do use it is easier to maintain. If it needs to swap to the opposite type of list in the future then that's an option, but I feel like I have zero free time at the moment so don't want to make this any more of an administrative burden than it needs to be.

 

I think most of the cheaper providers and new providers use CGNAT. Suggestion, list the ones we know. E.g. if we know CGNAT is used, list it, if we know CGNAT is NOT used list that. I notice, some people saying you can ask to have it disabled, or request a static IP. It would be good to cover those cases too. Just build it out with the info we have and put a date against each entry as a reference for when it was last checked.

And lastly, I totally understand you're busy, and thanks for your efforts.

I also like @deadlyllama idea of listing IPv6 support.