Create beautiful responsive sites with collapsible menus or regions with the Sidr module for Drupal, which lets your site go responsive with style.

If you're migrating or upgrading your site to Drupal's latest version, you'll be amazed by how many out-of-the-box modules are available.

That being said, there are still a set of handy contrib modules you'll probably use for most of your projects. This isn't a complete list, just a starting point for anyone new to Drupal looking for a useful set of modules to try. 

A detailed tutorial on creating custom fields in Drupal using the field API.