I've noticed a few of these in chat recently (that's the only lace they appear). There is not a wiki entry and nothing on the forums (that I could find). It seems like most Unicode characters are valid but since testing would require renaming my character, and that can only happen every two months, I think it'd be faster to ask the hivemind that is the forum.
Use this to Thread to post the character that you know work or don't work (please tell us which!)
if you know it, please provide the unicode# and/or keystroke too :)
If a dev feels like answering: is this going to be kept/tossed/integrated? Thanks!