Web Parts are nothing but another widget which is used for customizing look and feel, and control its way of doing its work with data stored. There are numerous OOB – out of the box webparts that can be used at ease. If none satisfies your need, you can also develop your own webparts using ASP.Net and use it effectively.
Below lists all the oob webparts that are available in Sharepoint 2007.
1. List and Libraries
All the lists and document libraries in your site collection
2. All web parts
Just hang on and come visit this page soon for webparts available in Sharepoint Server 2010.