As strange as it seems I think that accents are one of the best DHVs, but they have some pitfalls to avoid as well.
I would suggest the book "Accents: A manual for actors" or if you can afford them lessons. Having three or four good accents definitely makes you stand out from all the AFCs. And it allows you do open, in my experience, most any set with most anything you say. Last week I opened a 5 set with 2 8s and 3 guys by asking them where the bathroom was.
I knew where it fucking was of course, but it opened perfectly. I went into a couple routines, and then dropped the accent. They asked why my voice changed, and I used it as a neg "Come on you knew that was fake right?" which got turned into a DHV because they couldn't tell it was fake, which meant I was good at it.
But I got stuck in one of the pitfalls, as style calls it "performing monkey mode".
I got the same exact routines to work again on a 4 set 8,9 and 2 dudes during the day but this time wasn't performing, I even blew out a BF (the

. The girls started asking a ton of questions and I got some kino. It was great, the guys got annoyed and left. I had to go to class, so no closes, but it was nice to see it works outside of a bar.
I wonder if it could be an AMOG destroyer if done right?
Other pitfalls:
It has to be good/recognizable. Mine are mostly British: London, RP, Cockney, Australian, and then French.
Don't do it too long.
Try and avoid talking about it once you drop it.