Joseph Hinson

Do you have a lot of categories and are sick of having a huge list in your sidebar? Want to highlight only a few of them to make your site easier to navigate?
While redesigning WordPress sites for our clients we kept running into this problem over and over. They had a huge list of legacy categories but only wanted to highlight a few of them. We wrote this plugin to allow them to select which categories to show and which categories to initially hide.
All categories are still accessible by a “see all” link at the bottom of the list.
Add the widget to your sidebar to make it live.

Category Expander

Allows WordPress Admins to show only a selected few categories on the sidebar and hide the rest from view until visitor clicks "See All".

javierjara

This plugin adds a simple widget that you can customize easily it allows you to display a number of recent blog posts from a specific category. You have the options to choose a title, category, number of posts and whether or not to show the post date or to show the image featured (Post Thumbnails).The posts will be ordered by date just like the default Recent Posts widget included with WordPress. 
check the category you want to show.

Custom Recent Posts Widget Plus

Nice widget it is like the default Recent Posts widget except you can choose a category and in addition show the thumbnails.

Category Expander vs Custom Recent Posts Widget Plus