I see NJ plates fairly often, especially in Philadelphia itself.
Back when I spent more time in New Jersey - early 2014, to be exact - I definitely saw high numbers and unique plates galore. Sadly, I was not really "into" the hobby at that time, and thus have no photos from that period.
I am most likely to see non-resident temporary plates around here. Occasionally I get lucky and spot a passenger high. That's about it. I recommend checking out Jim Moini's site for more on NJ plates, including all NJ highs.