Archiving wasn't a streamlined process and with 9600 different topic ID's to check. Not only was there the risk of me missing some but also Google Cache sometimes didn't have the data when requested.
As such some topics that should exist are currently missing. Some deleted as they were spam created by bots and others removed by the author. 1180 topics were recovered in the process.
Glad you asked ;) archive.org is a great place to start looking for the content as their crawlers keep many versions of pages and retain the data.
If you're wondering how to even start finding content on the wayback machine then here is a link that will help. It's a pre-filled wildcard specifically looking at topics. Just modify the query with the topic number and see if the posts you're after were crawled by them. Then just check the latest working version and see if the page exists.
One of my topics wasn't cached and got missed during the initial collection phase. This was 9588 being the XS thread. However you can find it there using the provided link and adding the topic ID.
Now there are more advanced ways of doing this so if there is something you really wanted archived that cannot be found with the above method I might be able to be a bit more forensic with a search. You'll be surprised how much hidden post data NodeBB loads on a page if you know where to look.
All you need to do is copy the link to that page and comment below with it and I'll curate the data before merging it into the site.
Good luck and happy archiving ;)