domain name system – ADDITIONAL section – what kind of records can we find here?

From my little experience, we usually find A or AAAA records in the ADDITIONAL section.
I was reading an article that says:

In practice this section almost exclusively contains the A or AAAA (IP
Address) records of the Name Servers defined in the Authority section.

The “almost” confuses me a bit. What other records can we potentially find in the ADDITIONAL section?