What are some of the most pretentious cars?

Anything electric.

I do like the fact that people can hack into them and some people are resorting to using the low tech The Club™ on their high tech autos.

Oversize pickup trucks without mufflers

I work with someone who bought a Bronco for every member of the family - a total of FOUR. The 18 year old daughter was just gifted one for her graduation from high school. In my day when one was 18, we drove the car from the movie Uncle Buck or its equivalent.

In the area I live, even a garden variety BMW, Mercedes, or Lexus drips pretentiousness in my opinion. My dad loved Mercedes because he was a mechanic and fan of "German engineering" as he called it. He owned several used ones in succession as I was growing up. I was embarrassed to be seen in them. Even then I knew the air they gave off. I was jealous of my friend who was brought to school in a Chevy Nova.

IMO, all three are fairly plain looking and not in any way what I would consider to be flashy or pretentious. Of the three, I consider Range Rovers to be more "upper class" than the other two. I have several friends who own Teslas - just regular middle class folks who happen to like electric.

The Toyota Prius was probably the first major one where the pretentiousness was in the form of [false] "virtue signaling" rather than flaunting wealth. I seem to remember that there were even rich & famous celebrities buying them to bolster their standing in the Earth Worshiper cult.

As for flaunting wealth, Rolls-Royce has been the go-to make for that for ages. Most people who own those don't even drive them; they have a "chauffeur" (glorified taxi driver) instead. See also: Bentley. The highest-end Mercedes-Benz models are sort of up there too, but they also make, or have made, a lot of mundane cars, including cars that have been used as cop cars in some parts of the world.

Some rich people go in a completely different direction, buying an exotic sports car (e.g., Ferrari, Lamborghini). I don't consider those to be "pretentious cars," or at least, not as pretentious as something like a Rolls-Royce, because the people who gravitate toward cars like that tend to be "car guys" (Jay Leno is a well-known example; Steve McQueen is another) who are looking for a thrilling driving experience, rather than a luxury suite on wheels.

Most of my life I was a big Rolls-Royce fan. Beautiful cars with flowing lines. Now they are boxier (I especially don't like the front/grill), with so many features they just seem a bit pretentious to me.

Limousines are so pretentious that the rich stopped routinely driving in them.

Corvettes. I dislike anyone who owns one.

Signed, million man.