How to find all objects affected by a table definition change?

I am a dba supporting developers. They are wanting to know all objects that will be affected if they change the definition of a particular table. I have found that many different views have pieces of this information:

dba_dependencies

dba_views

dba_mviews

dba_source

I have gone through and pulled code using the dbms_metadata.get_ddl and instr'd on the table name. But now I need to also to do same for all the referenced tables. I can't be the first person who needs this information, so I am wondering if some script or utility already exists that I can use to find the information. This is the closest product category I see so asking here but if there is a better place to post the question, please let me know. Failing anything else, I'll write one, but I gotta figure it's