MySQL - forbidden database names
Run show schemas - the ones installed by default
are:


mysql> show schemas;
+----------------------------+
| Database                   |
+----------------------------+
| information_schema         |
| mysql                      |
| performance_schema         |
| test                       |
+----------------------------+


Just don't use any of these and you 
should be OK - is there any particular reason
for your query?

Further comment from the OP:


  My reason is that I allow my users to pick a name for their
  environment, and it implicitely creates a database with the same name.
  This is why I have to ensure my exclusion list is reliable.


But surely, even in the unlikely event that your users try and create a schema that already exists, the attempt will be rejected anyway?