dwfactory

<ol>
<li>Enter MySQL query to get data from your WordPress installation database.</li>
<li>Enter HTML layout with placeholders for your database results.</li>
<li>View your layout populated with data in a snippet position of your site.</li>
</ol>

DW Anything

Create custom database-driven widgets without programming.

Marinus Klasen

Different widget content on multiple pages? Exactly.
This plugin adds WYSIWYG editors on page/post level that can be filled with content. 
Add the widget to your sidebar and start editing on page level!

mklasen's Dynamic Widget

Add per-page/post configurable WYSIWYG editors as a widget to your sidebar.

DW Anything vs mklasen's Dynamic Widget