The Challenger and Charger are unique, mainly due to the nostalgia and similarity to classic muscle cars, more than any other modern vehicles on the market arguably.
In the nostalgia for classic muscle-cars and today's retro-designs, I'd also include the Mustang, Camaro, and, to some extent, the Chevy SS, though the SS admittedly has low production numbers. I would have said the Pontiac GTO, except that it's been out of production for some 7-8 years now, and, with Pontiac's demise, obviously won't be coming back.
(BTW, a little off-topic maybe, but
if Chrysler ever does a retro Road Runner, unreliable or not, my checkbook's ready. With Plymouth gone, it would have to be under the Chrysler name, as Dodge is already tied up with the Charger. I grew up with the original Road Runners, it was my favorite American muscle-car, and I was a s**ker for the bird-graphic decals, Shaker-scoops, and Beep-Beep horn. The original Road Runners, despite durable drivetrains with the TorqueFlite automatic, like most Chrysler products of the era, had atrocious build-quality almost everywhere else outside of the powertrain...that, of course, despite Chrysler still lagging in that department, would be far-improved in today's models)