I have come across many situations where I had to build a system for a library or a clinic or other popular domains.
The thing is a domain model for a library was probably done 1000 times already with different level of details of course. Here is an example.

Is there a popular website or community where one can find ready made domain models for popular systems?
The whole purpose I'm trying to achieve is to quickly get a grasp of the domain I'm modeling and customize it to my needs. Re-inventing the wheel seems really absurd when the same system might have been modeled properly previously.

Note
I know Google might sound like the perfect source, but there is a repository out there that people can post there models, so that others can share them.