Or just:
'K
(maybe not different enough for people to readily distinguish)

I love pil's suggestion of Special K, but that is the name of a cereal here!

I'm no help! I couldn't even think up a something for myself, hence I just used my first name:). For some reason I think you are an attorney?? How about "Counsellor" ...see told you I'm not very creative lol

I'd go for something short like TheK (I like Anna's suggestion of spelling).

K-POW
K!
w/K
J/K

0K because you are so cool.

I love the Oh-K suggestion!