A new batch has been cooked up by my brother; just in time, since I’m fresh out.
If you found yourself in charge of a charity with essentially limitless resources (ala the Gates Foundation), what would be your “cause”. Mellon was libraries, Carnegie was the arts, Gates is health. What would yours be?
Assuming the other foundations mentioned are still around, I’d go for theatre with the goal of promoting it in schools and encouraging new playwrights.