Just a random thought, but has anyone ever seen or heard of a compiled survey of what lies in private and institutional collections of US and European metal fonts around the world?

Would be nice, but I’m afraid many of the owners of these collections don’t even have proper catalogs. 
I feel so lucky that we could finally catalog our museum’s foundry type this year through an internship—after the museum existed for 25 years. https://pavillon-presse.de/archiv/font/buchdruck/

That's an impressive collection, and obviously very organized. Does the museum allow the fonts to be printed from?

18 hours ago, George Thomas said:

Does the museum allow the fonts to be printed from?

Most of it is available for design projects and workshops. Some rare or fragile fonts can only be used by skilled typesetters.