I recently have come to learn that there are 6 types of Event Receivers that can be done in SharePoint 2010. I thought I could share them here.
List Events -
Adding/ed a new list field.
Updating/ed a field.
List Item Events -
Adding/ed a new list item or document.
Document checking/ed in or out.
Adding/ed an attachment.
Deleting/ed an item or document.
List Email Events -
A list received an email.
Web Events -
Deleting/ed a site collection or site.
Creating/ed a new site collection or sub site.
Feature Events -
Feature activating/ed or deactivating/ed.
List Workflow Events -
A workflow is starting/ed, postponed, or completed.
Thanks to Isha.