The DB is the foundation

Call me archaic or protozoic, but I still believe that the design of any application starts from the DB.

I like to get the DB structure first, then do:

for all columns:

select * FROM USER_TAB_COLUMNS;

for all tables:

select unique(table_name) FROM USER_TAB_COLUMNS;

you can stick the result in an Excel and generate from it plenty of useful stuff...