reddit has little tags that you can pick out related to the subreddit you're in that go beside your username when you post anything. For example, in r/AskMen (and a lot of the other "ask" subreddits) there's a flair you can use that indicates whether you're a guy or a girl and what age range (e.g. "Male 30-35", "Woman 30+", etc.). Some subreddits have silly references, quotes, or in-jokes.
I've seen on other forums where they use fluff badges that you can choose from (in some cases purchase, but I wouldn't recommend that) to put below your username, much like your "Admin" badge, but with less official designation. Might not work as well here since we already have the profile images, but YMV.