Extensions are installable packages which give CiviCRM new functionality, and this directory provides a centralized list of extensions which the CiviCRM community has created.

Further resources:

Send email notification to event speakers when a new individual registers....
Current Usage: 0
CiviCRM native extension to check if the CMS is in maintenance mode when I get a REST API and return error if so.
Current Usage: 0
This module is intended to improve code quality. At this stage it simply causes 'very wrong' html to spit out errors. Hopefully we can refine it over time to set developer settings & highlight other dev things. Potentially it could be enabled when webtests are running & webtests could check for absense of errors?  ...
Current Usage: 0
This extension provide payment processor with PayLeap payment gateway....
Current Usage: 0
Ensures that the creditnote_id field is filled out with a sequential credit note number for refunded contributions
Current Usage: 0
The Drupal core contact module provides a no-frills way for users to email you via a simple webform. If you like that module, but would also like those form submissions to be recorded in CiviCRM, then this no-frills extension is for you....
Current Usage: 0
This is an integration module for sites running CiviCRM and the Domain Access module.  By default, when creating a user in Drupal, Domain Access will automatically assign the user to the domain on which they registered.  However, if they create their user via a CiviCRM profile, they will not be added to the appropriate domain.  This module fixes that....
Current Usage: 0
CiviCRM WordPress Member Sync keeps a WordPress user in sync with a CiviCRM membership by granting either a role or capabilities to a WordPress user who has that membership. This enables you to have, among other things, members-only content on your website that is only accessible to current members as defined by the membership types and status rules that you set up in CiviCRM....
Current Usage: 0
This is a drupal module for drupal sites using civiVolunteer and views. It makes civivolunteer tables (Volunteer Projects, Volunteer Needs and Volunteer Project Contacts) available to views so that site administrators can create views of civiVolunteer opportunities, projects etc.  ...
Current Usage: 0
You can use this CiviCRM extension if you want to create a settings form for your own extension.
Current Usage: 0
This plugin integrates the Joomla and/or Community Builder registration process with CiviCRM....
Current Usage: 0
The CiviCRM WordPress Profile Sync plugin keeps the "First Name", "Last Name", "Email Address" and "Website" fields of a WordPress (and BuddyPress) user profile in sync with the corresponding fields of a CiviCRM contact. The synchronisation takes place regardless of whether the changes are made in WordPress, BuddyPress or CiviCRM....
Current Usage: 0
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Current Usage: 0
Allows a contact's Do Not Contact preferences to be marked with dates when that preference will expire....
Current Usage: 0
Allows Zaakpay payment processor to be used with the civicrm. More info at Extension page on github...
Current Usage: 0