The sidebar hosts panels for working with particular document types. Panels vary depending on document type and editor. The following is available with html and xhtml (in WYSIWYG mode):

For editing attributes of DOM elements. You can add, remove and edit existing attributes in this panel.
Choosing Editor > Context Menu > Edit Attributes opens this panel.

Add bullet lists (ul) and numberings (ol) at the cursor position. A non-collapsed selection gets converted to a list. You can also switch the list type by pressing "bullet list" when inside a numbering and vice versa.
Create and edit nested lists with the "indent"-buttons.

The table panel hosts a set of commands for table editing. Available commands:

The link panel has tools for editing existing links.

This panel lets you insert, select, edit and remove anchors.