The ASP.NET AJAX Control Toolkit is a classic set of ASP.NET WebForms extensions that helps you build ASN.NET websites. Now maintained by devexpress.com

Real World implementations of custom controls for ASP.NET.

Resource Refactoring Tool is an add-in for Microsoft Visual Studio 2005 Standard or above that allows developers to refactor string literals in to resource files directly from the code window.

Self contained Rich Text Editor ASP.NET

Snippet Designer is a Visual Studio plug in which allows you to create, edit and search for snippets inside the IDE.