When I got my license about 50 years ago, I believe the only punctuation marks on the test were the period, comma, question mark, and slash mark.
Once on the air, I heard and used the usual prosigns, [AR], [BT], [SK], [KN]. I also frequently heard and used [HH] to indicate an error, and dit-dididit (the American Morse ampersand). There were a few others less commonly used but generally understood when I started out: [AS] (wait), [VE] (acknowlegement), didit-dit (American Morse C, used to ask if frequency in use). Also [AA], used only in formal message handling as a separator.
I wonder if anyone has actually used any of these other characters, or heard them being used. Do hams who converse on CW in languages other than English ever use the accented characters? Is anyone using the new at sign (@) character that was added relatively recently? Who ever used those additional punctuation marks?
This is not an question about opinion as to whether or not the use of these characters is a good thing. It is also not a question about whether these other characters have been documented on paper or on the internet. This is a question about under what circumstances and at what times these seemingly-rare characters have been used on the air as a regular practice, rather than a theoretical possibility.