The ones that a missing are old and may have been moved around. I’ll see if I can find them or updated versions. Was there a specific one you were interested in? (Ping me on Twitter or @gmail if I forget to reply here.)
All of the ones that I clicked on seem to be missing.
The first three illustrations on the page are all 404 links. If someone is maintaining this site, it's crucial for every link on a page like this to work.
Some are accessible. Can find the accessible ones here: