To make things easier, run the Analyze Database function in the Tools menu. This function goes through your database, looking at all fields in all tables for fields containing meaningful data (that is, more than a single unique value), and marking those as "favorite." This may take some time to run, depending on the size of the database. For example, a database with 1,000 tables and 35,000 fields and tens of thousands of records took about two minutes to run.
After you've run this function, step 2 in the report wizards displays a button with beside Table. If you turn this on, the table and field lists show only those tables and fields marked as "favorites." Turn it off again to display all tables and fields.
You can run the Analyze Database function more than once. For example, if a new version of your program is available, it may add numerous tables and fields, so this function can update your favorites list.