If I was a benevolent and wise billionaire I would donate money to advocate for increased immigration and liberalization of agricultural markets.
But that's boring.
There would definitely be some ducats handed out for AI research. But that's still not worth writing a post about.
If I was an eccentric and slightly misguided billionaire who didn't care at all about philanthropic ROI, I would donate materials to public libraries. (Note: not money. I wouldn't trust them not to waste it on more administrative staff or other government sector bullshit. I would pay for materials acquisition or facilities maintenance directly.) But there would be an important stipulation: they have to make their catalogs accessible to a public API so people can write their own applications to access the catalogs.
Hopefully from this post you can judge on a scale of 0-10 how pleased I am with the quality of the library catalogs I interact with.
(The answer is zero.)