There are over six thousand modules available for Drupal 7 and even more available for Drupal 6. It can be hard to find the modules or module combinations that fulfill the need.
My Most Used Modules
Views - If you’re not using this module, you are working way too hard and not letting Drupal do the work for you. This module is so widely used in websites and so powerful that Drupal has adopted it into its core release in version 8.
Google Analytics - As a digital marketing developer, how can I not include the largest search engine tracking code?
Pathauto - Along with the SEO value of the Google Analytics module, Pathauto creates human readable and SEO-friendly URLs automatically. It does this without requiring the user to manually specify the path alias.
XML Sitemap - Going right along with SEO, with this module I configure what content I want the search engines to know about. I then leave the page ranking to the site editors. This module creates the sitemap.xml conforming to the sitemap.org specifications and sends this information to the search engines automatically.
Menu Block - Instead of creating different menus for the sidebars, header, and footer menus that contain the same links, I use this module to display subsets of a master menu. This makes it easier on the maintainer when updating menu links. One change to a menu link can affect multiple menus on the site. I also use blocks from this module to build the menu structure on the sitemap page, as the sitemap modules I have tried so far do not sort the menus the way I would like.
Node Embed - Just like Menu Block with menus, Node Embed allows me to place content in multiple places and embed one piece of content into other content. The main place I use this module is when working with calls-to-action (CTA) content. It allows me to edit the CTA content separate from the article content where it appears.
Administration Menu - I do not like the default admin menu setup in Drupal. It requires too many clicks to navigate the administration of the site. I have tried a couple admin menu replacements and I like this one the best. It uses drop-down menus to make navigation a lot easier. Enabling the included Administration Menu Toolbar Style module gives the menu a better look and feel. I have one big issue with this module: it is not designed to handle a site build on responsive design well.
Webforms - I use this module on nearly all my projects for the Contact Us forms. It will send the visitor a customized thank you message. Then it will send submission notifications to administrators or Sales Teams for followup.
SMTP Authentication Support - I recently had an issue with a client in which email notifications were not being received by their email server. We found that the server was rejecting the email because the site was on a hosted service and failed a reverse lookup checking for spam. This module enabled the site to send email through the domains registered email server through SMTP. Problem solved. Now I am including this module in all my projects.
These are just a few of my more favorite contributed modules that I use. The best thing about Drupal is not the code, but the community. Sharing our experiences expands that community.
In the comments below, let me know which modules you are using and why.