The Sidebar Content widget is used to add a heading and custom content in the left or right sidebar. 

(Sample Top Left)

The Sidebar List widget is used to display a list of pages by selecting a location where these pages are contained. You can create your list under a folder or point to an area of the content tree to display the child pages. (Used with the "Page" page type.) 

(Sample MIddle Left)
 

The Sidebar Search Box widget provides a text box where users can enter search expressions in the sidebar. Searching redirects users to a page that displays the search results.

(Sample Left)

The Sidebar Sub-menu Link widget provides the capability to add a link under the Navigation section in the Three Column Layout as part of the sub-menu.

(Sample Bottom Left)