NO NICKNAME NAMES. I can always find a good nickname in any name. My partner's mom named her sons to have no nicknames: Jason is now Jay or Jase and Branden is B or Denny, etc. But if you want a name that will usually be said in full (no obviously accessible pet forms for people to pluck out of thin air), try starting with these.
All of the names below have been given to at least 5 American babies per year every year since 1900, without any sharp popularity peaks that would date them. These names are all over the style map but they're all timeless, and not a James or Elizabeth in the bunch.