I trust yours is a hypothetical question.

Each of the members of your set of characters is special at times, but, AFAIK, they are not all special in the same context. Can you clarify the case (context) in which (you think) this might be true?

One might adduce from the first sentence in your question that you believe they're special in a string: That's no so in any circumstance that occurs to me (even though ' and " are used when assigning strings to variables, and thus require escaping if either occurs inside a string quoted with itself.