CB750 four, first four cylinder inline from Japan. Set the scene for Japanese bikes.
The Z1 (obviously).
CX500. Odd design, ran forever on little maintenance (but when you had to work on it then it was an absolute swine). Ugly as sin, sort of looks like 70s brutalism today. Still quite a few about.
GT550 (Kwak). The yardstick of reliability and a sucker for real abuse that didn't look like a CX. Again, quite a few still about.
GPZ900R. The first modern superbike. Goes like shit of a stick, handles well, comfortable and a well respectable sports tourer even by modern standards. Plenty on eBay for next to nothing, I've seen them go for as little as £300. Quite fancy one myself as a project like.
Slab sided gixxers? Well, maybe. Shame the fairing hides the beautiful engine. The Bandit? A possibility, brought the gixxer motor back to those of us that prefer Renthals to clip ons.
Apart from that, there's got to be a two stroke triple in there, I'd go for the Kwak.
RD350LC YPVS. Most certainly not the TDR or the YZR though.
250 Gamma? Almost seems to duplicate the power valve but then these were insanely fast, incredibly sharp handling little bikes that weighed about as much as a skateboard and you could probably carry one around in your pocket.
Yam Tenere. I'm biased, feel free to disagree. Still the best of the big single trail bikes though. Tall feels so dated now and put alongside an XR400, tall feels very dated as well.
One thing I can add is the CR500. The meanest, nastiest, dirtiest, most vermicious, surly, growly, foul tempered crosser ever.
I guess that's a whole new section. Classic Japanese track bikes.