Copyright/trademark violations, shouting "fire" in a crowded theater, direct personal threats of bodily harm, basically a lot of stuff which is already widely considered to not be protected speech legally, but which is "speech" in the plain language sense of the term (and importantly, not exactly an "idea" in the plain language sense of that term).

I think it helps strengthen the argument rhetorically, since people can't as easily use the existence of such "exceptions" as an argument for adding more, or bypass the principle entirely with slogans like "freedom of speech isn't freedom of reach". (Suppressing the "reach" of certain ideas does inhibit their free exchange.)

This approach hasn't been "battle tested" yet though so we'll see how it goes in practice.