taxonomy_similar will display a "similar tags" screen anytime content has been created or updated with tags from a "Free tagging" vocabulary. This module requires no configuration.
This module allows visitors to the site to volunteer for an event and provides the site administrator with comprehensive Volunteer management tools to keep track of Volunteers, tasks and communication.
RSVP lets users invite people to attend an event. Users create an 'RSVP' from an event, send an invitation email to a list of people and then track who has looked at the invitation and their responses. Invitees can view and reply without having user accounts.
RSVP creators can be setup the RSVP to hide other attendees, allow attendees to send email messages to the group, or invite more attendees.
The Media module provides an extensible framework for managing files and multimedia assets, regardless of whether they are hosted on your own site or a 3rd party site - it is commonly referred to as a 'file browser to the internet'.
Media is a drop-in replacement for the Drupal core upload field with a unified User Interface where editors and administrators can upload, manage, and reuse files and multimedia assets. Any files uploaded before Media was enabled will automatically take advantage of the many of the features it comes with.
Media's aim is to solve Drupal's long standing media handling problem.
Drupal 8
Drupal 8.4.x now comes with a module called 'Media' that is similar to the D7 version. It is included in core as of 8.4.x. See this documentation on how to configure the 'core' module , no need to download this module it is included in D8/D9/D10+ core releases.