IMO the Nokia-style "candy bar" phone is the iconic mobile phone design globally. I don't think I've ever seen a "generic cell phone" drawing that would be a clamshell design; usually it's something that looks vaguely like a late '90s Nokia with the antenna stub.
More specifically, I'd say that the Nokia 3210 [1] was one of the most iconic and recognisable mobile phones. It was the one that came with Snake and created the fad for comparing high-scores amongst friends.
I'm not ashamed to say that I'd be using a 3310 now but you can't get reliable batteries any more. That leaves only later Nokia dumbphones which are the same in spirit but inferior in usability.