The free Component Architect product provides enough capabilities for you to define extensive Joomla components with multiple tables and as many fields as you wish.  It has a full set of standard Joomla! field types to select from when defining you fields and you can organise the fields into any number of fieldsets that you require.

Although free, Component Architect still allows you to define unlimited components/extensions, objects/tables, fieldsets and fields.  Plus you can regenerate you components as often as you wish.

 An added feature to speed your component definition is the Component Wizard which allows you to quickly define the component/extension and its objects/tables.  You can then change the default settings for the features and functionality that will be generated in the component/extension and refine this further for each object/table.  When you set the features and functionality settings for the object/table then this will automatically adjust the fieldsets and fields for that object/table by adding and removing pre-defined fieldsets and fields

If you wish to remove/delete any part then you can just select it from the appropriate list and click Delete.  This will delete not only the record selected but all child records (e.g. if you select to delete a object/table then all fieldsets and fields for that will also be deleted)  Note: you cannot remove/delete a pre-defined fieldset or field directly from the fieldset list or field list.  They can only be removed/deleted by changing the generation settings in the relevant object/table.