Following are the Drupal modules:
The Content Construction Kit (CCK) is a Drupal module that allows for the easy creation of custom content types with custom fields. While this module is not in itself a theming tool, it does allow for more flexible layout of your site. There are a number of options that can be combined to extend the functionality of CCK, making this a very powerful—and widely used—extension.
The Content Templates (Contemplate) module can be combined with CCK to enable easy control of the Drupal teaser and body fields.
Learn more: http://drupal.org/project/cck see also, http://drupal.org/project/contemplate
The Devel module is a suite of tools that are useful to both module and theme developers. This extension was used for several purposes in this book: revealing information about themes, providing dummy content, and identifying recommendations for overrides.
When creating intercepts and overrides, you will find the Theme Developer option particularly useful, as it provides quick access to key information about the templates and functions being used by each page. The Theme Developer option is included with the Devel module, but must be activated separately.
The option to create dummy content quickly and to your specifications is also a real time-saver. No more time wasted, spent creating dummy users, content items, and comments by hand. Again, the Create Content option is included with the Devel module, but must be activated separately.
Note
This extension is intended for use during development and should not be employed on a production site.
Learn more: http://drupal.org/project/devel
The Panels module makes the creation of multi-column layouts a breeze. With Panels, you are able to divide a page into content areas and control the content in each area. Blocks and nodes can be mixed freely.
The system comes with several default 2 and 3 column formats, but you can do virtually anything you want with a little configuration work.
Learn more: http://drupal.org/project/panels
The Views module enhances your control over the listing of content items (nodes). With views you can create custom lists that contain the content you want, sorted in the manner you want. Views makes it easy to make blog-site type lists of the most recent articles, most recent comments, top posts in a category, most popular posts, etc.
Learn more: http://drupal.org/project/views