Some I know:
Scratch.mit.edu/abouta
Scratch.mit.edu/500
Scratch.mit.edu/429

Any more?

https://scratch.mit.edu/news
Pretty infamous one, though

I found scratch.mit.edu/camp (which was from 2017 and I don't know why its not deleted)

medians wrote:

Well, there's actually a topic for secret scratch pages in the ATs, so you could probably check there.

Thanks for the link! It does look like this is a duplicate topic so I'll close it to keep the conversation all in one place.

Please use the existing topic in the link above.