1. Arts<snip>
2. Collectables<snip>
3. Real estate<snip>
The super-rich buy the first two categories mainly for their own enjoyment, because they can afford to, and presumably because they think they can eventually resell those things at a higher price down the road--but I don't think either one are considered primary investments for the 1%'ers. I think they're mostly decorations for their mansions.
Real estate I agree with, and just look at Donald Trump. He made his fortune in real estate, as did many other billionaires. I wish I had enough dough to buy some land, but the best I can do as far as investing in real estate is buying REITs on the stock exchange.
A lot of uber-wealthy individuals also invest in businesses, and I'm talking privately (not on the stock market). I've heard many sports stars putting their money into restaurants and the like, and those all generate income. What the ultra wealthy don't do is invest in extremely risky assets like crypto, unless it's a very small fraction of their total net worth. Their priority is keeping their wealth safe, not increasing it.