Most of the people I know who go by initials use J: AJ (Anthony James), PJ (Paul Joseph), GJ (Gregory Joseph), JR (John Ryan), and JP (John Paul) were the first I thought of. Most of those are called by their initials because they are Juniors or IIIs, to differentiate them from their dads.
The only friend of mine I can think of who goes by initials that don't include J is AK (April Kristin), and she doesn't go by that all the time. It was something that came up when she played sports in high school to differentiate her from another April on the team, but it never really "stuck" as a nn full-time. Some other friends who go by double-names get called by their initials occasionally, but it's not a very regular thing at all (AR for Anna Ruth, EG for Emily Grace, and KB for Katie Beth (also a nickname -- full name is actually Katherine Elizabeth)).
Re: Any other nn using initials other than J as in DJ, AJ for example?
I've known people who went by:
DC-- Darius Christian
LL- Lorenzo Lucas (but this always reminded me of LL Cool J)
JC- Julia Christine
KC- Keith Christopher
JL - Jesse Lawrence
JB- I don't know this person's actual name
MB- A nickname for Mary Beth
JT- John Thomas
JP- Justin Paul
The only friend of mine I can think of who goes by initials that don't include J is AK (April Kristin), and she doesn't go by that all the time. It was something that came up when she played sports in high school to differentiate her from another April on the team, but it never really "stuck" as a nn full-time. Some other friends who go by double-names get called by their initials occasionally, but it's not a very regular thing at all (AR for Anna Ruth, EG for Emily Grace, and KB for Katie Beth (also a nickname -- full name is actually Katherine Elizabeth)).
I know a PK (it's actually first initial and last initial because he has a hard-to-pronounce name).
TC- thomas charles
JP- john paul
JR- john raymond