is there a list of every Scratch warning message?
I know there's a message about Sprunki, but is there a list of every possible warning message?
I genuinely want to know.

there's not a list of warning messages but there is a list of messages that you get when you get banned on the scratch fandom

well, there are well known ones like “you are now a scratcher”, “you can comment again”, “the scratch removed your project because ____”, and whatnot.

Check Scratch's translation repo.

I don't have screenshots of mine, but I remember getting tempbanned and having that message.