Component Definitions - Free
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.