If you're looking for a quick way to document code blocks, this plugin prompts for a custom note and inserts comments with the note at the top and the bottom of the selected text.
Importing text from files not originally intended to be used on the Web? This plugin can be used to convert special characters in plain text blocks to HTML entities.
HTML-Kit has built-in support for dragging and dropping some of the most common file types. This feature can be extended to cover other file types, or the tags inserted by default can be customized as necessary.
Demonstrates how to write a drag and drop handler in hkScript that can insert either <link rel="stylesheet" ... /> or <?xml-stylesheet ... ?> depending on the doctype.