Useful Modules and theme From Drupal Case studies

1. Share buttons for Drupal including the AddToAny universal share button, Facebook, Twitter, Google+, Pinterest, WhatsApp and many more. :   https://www.drupal.org/project/addtoany


2. Provides the ability to use external files with file fields without saving the files to your local files directory. Also provides a 'Remote URL' browser plugin for Mediahttps://www.drupal.org/project/remote_stream_wrapper

3. Accelerated Mobile Pages (AMP)

4. Aegan Theme based on Bootstrap https://www.drupal.org/project/aegan 
5. Twitter Block Twitter Block is a lightweight module which allows administrators to create 
6. HSTS: HSTS (HTTP Strict Transport Security) is a standard used by HTTP client applications to enforce the use of SSL communication between a site and the client. 
7.      security modules
   https://www.valuebound.com/resources/blog/implement-these-modules-make-your-drupal-site-more-secure .