Chao & Eero make the best ones, although they lean more towards geek symbolism since they also carry =) smileys and speech bubble rings from comic books etc. A+ for innovation there, the shapes are genius if a little esoteric. Loving the subtlety of the comma necklace though. 

Then, of course, Etsy has become the go-to stop for all things quirky or handmade. Below: something unisexy, something statement, something gaudy-fab. 

What I've noticed: exclamation points and question marks are the easiest to find. Commas and quotation marks come after that. The poor colons and semi-colons are nowhere to be found, although the semi-colon is my favourite form of punctuation; it allows me to continue a different-but-related thought in one sentence without having to stop typing or thinking. See what I did there, illustrating my example with a semi-c for you all?