Cleanup after deleting a large table
No other clean up should be required.  If you are really worried, you can watch your database size with:

select pg_database_size('your_database');


To make sure it shrinks by about the amount you expected.  It could take until the end of the next checkpoint to fully clean up.

If you were dropping tens of thousands of small tables is where you have you to worry about catalog bloat.  One large table is not an issue.