Please note the following commands:
\list
or \l
: list all databases
\dt
: list all tables in the current database using your search_path
\dt *.
: list all tables in the current database regardless your search_path
You will never see tables in other databases, these tables aren't visible. You have to connect to the correct database to see its tables (and other objects).
To switch databases:
\connect database_name
or \c database_name