Get the details of important oracle parameters such as "PASSWORD_LOCK_TIME" and "SESSIONS_PER_USER" etc
select * from dba_profiles order by profiles
Get the Name of the oracle instance
SELECT sys_context('USERENV','DB_NAME') AS Instance FROM dual;
Get the name of the current oracle instance and user id
select name,user from v$database
Query to see who has access to your package
select grantee, table_name, privilegefrom dba_tab_privs
table_name = 'YOUR_PACKAGE_NAME'
I will keep adding other usefull queries here....