AjaxControlToolkit contains a rich set of controls that you can use to build highly responsive and interactive AJAX-enabled Web applications. AjaxControlToolkit contains more than 40 controls, including the AutoComplete, CollapsiblePanel, ColorPicker, MaskedEdit, Calendar, Accordion, and Watermark controls. Using AjaxControlToolkit, you can build AJAX-enabled ASP.NET Web Forms applications by dragging-and-dropping Toolkit controls from the Visual Studio Toolbox onto a Web Forms page.
$ dotnet add package AjaxControlToolkitNo README available.