The OP requested UNCOOL cars… An E30 325i Sport is/was the epitome of cool… At least for me growing up anyway!
As for uncool cars that were actually quite good… I had a Citroen Xantia Active 2 litre turbo at one point. Seriously torquey engine, decently quick, cornered like it was on bloody rails due to the ridiculously clever suspension setup. By flipping a lever on the centre console you could either slam the car on the floor (for showing up the chavs with their cars with “only a 50mm drop” in the carparks on a friday night), or raise it up so it had almost 12 inches of ground clearance! It had a huge boot too, was massively comfortable.
In fact it had everything going for it, except… Well, it was a Citroen! Which meant it was bloody unreliable, and it was designed with a ruler and a set square. Cool, it was not! Oh, and it drank petrol too…
As for other old cars I’d secretly like… Well, a Volvo 240 Estate is so uncool it’s actually cool. They were built like tanks too, it would be the prime candidate for creating a monster street sleeper with a heavily turbocharged engine! That or a Volvo 360… A decently quick hatchback with rear wheel drive, and massive reliability, if not any cool factor at all.