@mrweaseluv, my goodness! I looked up an article that states a display of 4 Nova C coins by PCGS at the Chicago ANA coin show was insured for $15 million...must be some coin.
So this is a more personal grail for me. This is a Nova Constellatio pattern which I was lucky enough to see in person back in 2017 at the Denver World's Fair. This is a 500 unit denomination also known as a Quint. My Last name is Quint. Imagine owning a coin that you share a name with. And it's unobtainable.
A great many collectors are drawn to the 1907 High Relief $20 gold. I have called it the most common, very expensive U.S. coin. The mintage was 12,367 and probably 80% of them have survived. That comes to over 9,000 coins with a goodly number of them in various degrees of Mint State. Even so, it's hard to find one for much under $10,000. Usually it's a lot more.
My favorite, of which I've collected numerous from a fine to MS64 over the years! That looks to be a GEM coin, what is the grade? Beautiful!!
For me the unobtainable unless something changes massively a 1822 $5 and a 1873-cc no arrows dime. For me maybe obtainable a 1794 flowing hair dollar a 1796-7 small eagle half and a 1792 half Disme. All will be pricey and may not be pristine. But they could happen in time
For me its anything GOLD, currently on the prowl for a 1908 Saint ( Wells Fargo ) high mintage but high dollar !!