In MySQL can I drop a database by moving the directory containing the database?
SHOW DATABASES;


I suspect it will not show the database that you "moved".

Moving (or deleting) the directory would be unsafe it it contained any InnoDB tables.  It is safe for MyISAM tables, and probably MERGE and Archive.

ibdata1 contains information about InnoDB tables.  Non-InnoDB table types are discovered by looking in the file system.