In no particular order.
Earlier, single mirror Testarossa. Ask anyone to picture an "exotic" or "super" car, or hell, even "Ferrari". More often than not, this is the mental image that shows up. The quintessential Ferrari. You could NEVER sum up Ferrari's history without mentioning the 2nd car Ferrari ever called "Redhead".
Pre-facelift 928 with the rubber front and rear spoiler. Nothing captures 80s excess more. All the luxury of an S-Class, with the performance of a 911 (slightly better, even). I unashamedly LOVE this car. Always have, always will.
Ferrari 288 GTO, because, holy shit, do I even have to explain?
FD RX-7. If I had to narrow this list down to top 3, this is the only car that I can 100% guarantee would make it, without even having to think about it.
VW Beetle. Seriously. Although it comes from a…..less than ideal background…..I can't for the life of me think of a single more timeless design. It isn't just a car design, it is THE Car Design. What does that mean? I have no clue. Just look at it and smile.