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:

In version 4.7 and up, CiviCRM ships with only CKEditor, and other wysiwyg editors can be added via extension. This extension makes TinyMCE available as a wysiwyg editor for CiviCRM....
Current Usage: 251
This extension adds a block to the contact summary that allows editing of any configured relationship type with a UI similar to the employer field.
Current Usage: 251
This extension is designed to preserve the email reputation of your server and its IP by ensuring that all outbound email is sent from an address with the same domain as the System-generated Mail Settings From Email Address configured at Administer > Communications > Organization Address and Contact Info (civicrm/admin/domain?action=update&reset=1)....
Current Usage: 238
The Advanced Fundraising extension provides a series of reports to help fundraisers view their progress in greater detail....
Current Usage: 238
Creates Tax Receipts including single or annual/aggregate tax receipts, with distribution by email or print, detailed reporting, press ready PDF template possible. We worked with (and continue to work with) a BDO Tax Partner who has strong ties to both the NPO community and Tax Authorities (CRA)....
Current Usage: 236
Extension to facilitate postcode lookup feature in CiviCRM using AFD, Civipostcode, Experian, PostcodeAnywhere or getaddress.io providers.
Current Usage: 235
If you are in Europe and use CiviCRM to manage recurring contributions, you need this extension. Warning: upgrading to 1.2.4: If you're using the payment processors, please verify and re-save your payment processor settings! If you've been using the SEPA tokens, you'll have to adjust your templates SEPA Direct Debit Module...
Current Usage: 225
This extension loads United States counties when you first install it.  Once enabled, it does nothing.  You may disable it or uninstall it, and nothing will happen: the counties will remain loaded in your database.  If you re-enable it, it will check for missing counties and just add those....
Current Usage: 224
The CiviMobileAPI extension (com.agiliway.civimobileapi) is a CiviCRM component that allows to use a mobile application CiviMobile.
Current Usage: 223
Multisite (url) based permissioning.   This is a port of the drupal multisite module to an extension. It allows the CiviCRM multisite concept to be extended such that the site a contact logs onto will affect which contacts they can see and edit....
Current Usage: 222
Omnipay is an open source payment processor library that supports multiple payment processors (around 30 currently). https://github.com/omnipay/omnipay...
Current Usage: 219
This Hebrew Calendar extension for CiviCRM has a variety of functionality,  including mail merge tokens for sending yahrzeit reminders, birthday wishes, Hebrew demographic information, Hebrew date of birth, next Hebrew birthday, yahrzeits, APIs and more....
Current Usage: 215
This extension allows a staff user to add, edit and delete line items of a contribution.
Current Usage: 214
This extension adds a pivot report that suppots multiple CiviCRM entities.
Current Usage: 204
Displays CiviCRM events in a calendar using the "fullcalendar" jQuery plugin.
Current Usage: 176