The US has really more freedom. For example, you can call your kid whatever you want. In Germany you have some bureaucrat going through a list of allowable names. There is a lot of stuff like that.

But the average US citizen doesn't exercise most of these freedoms but actually lives a more restricted life than the average German citizen in my view.

> you can call your kid whatever you want

"several states limit the number of characters that can be used due to the limitations of the software used for official record keeping." and "The Office of Vital Records in California requires that names contain only the 26 alphabetical characters of the English language. Some states (for example, Alaska, Hawaii, Kansas, North Carolina, Oregon) allow accents and some (not always all) non-English letters in birth certificates and other documents." https://en.wikipedia.org/wiki/Naming_in_the_United_States

So, it's a long way from total freedom, but I get your point. However, you can call your kid whatever you want, the limit is simply around what you can do with official paperwork.

There is no fixed list - AFAIK you need to prove that it's a first name in use somewhere in the world, with a few exceptions. "Jesus" is one I know about, it's a valid first name in Spain but not in Germany.