Query the V$DB_OBJECT_CACHE table to find objects that are not pinned and are also large enough to potentially cause problems

You can query the V$DB_OBJECT_CACHE view to determine PL/SQL that is both large and currently not marked “kept.” These are objects that may cause problems (due to their size and need for a large amount of contiguous memory) if they need to be reloaded at a later time. This will only show the current statements in the cache.
The example that follows searches for those objects requiring greater than 100K.
select name, sharable_mem
from v$db_object_cache
where sharable_mem > 100000
and type in ('PACKAGE', 'PACKAGE BODY', 'FUNCTION',
'PROCEDURE')
and kept = 'NO';

Note: the above is copied from "Oracle Database 10g Performance Tuning Tips and Techniques" book.