In the openEHR (EHR = Electronic Health Record) project, we use a serialisation that is called ODIN, an alternative to JSON, XML etc. It was developed before JSON existed, and is more comprehensive (particularly in terms of leaf types). It is also (in my view) easier to read. It's certainly easier to write (in JSON,  and "" will eventually drive you crazy).
I know that many Eiffel libraries are quite well known, mostly the ones shipped with Eiffel Studio, which also includes Gobo Eiffel libraries.
However, even among those libraries, there are a few that are barely known by the users.