AndrewUlrich

This plugin creates two widgets:
<ol>
<li>A widget where you can choose from all the categories in your blog.</li>
</ol>
This is similar to what newegg.com uses, where you can select multiple categories, and it will only show posts belonging to all the categories you select, and such categories can be narrowed down by selecting their subcategories.
<ol>
<li>A widget where you can choose from all the tags in your blog</li>
</ol>
You can select the tags you want to search for, and it will only show posts that have all of the tags you selected.
<h3>Known Issues</h3>
After upgrading from 2.1 to 2.2 it is highly recommended that you deactivate the plugin and then re-activate it. Unfortunately WordPress 3.1 no longer calls register_activation_hook when the plugins are upgraded, so this may be necessary, otherwise you may not see all your categories.
When using version 3.2 or above, and excluding categories, the display order may or may not be mixed up when you exclude a parent category.

Faceted Search

This plugin will create widgets that you can use to conduct faceted searches using the categories or tags on your site.

Pratik Shrestha

Catch Plugins

Sakin Shrestha

dreamsapana

Catch Themes

Mahesh Maharjan

Essential Widgets – a free WordPress plugin for widgets allows you to create and add interesting widgets on your website to make it more attractive and welcoming. Essential Widgets stays true to the essence of its name and offers exactly what you expect from a widgets plugin—all the “essential” widgets for your website. The plugin has been crafted beautifully to draw the extra attention to the important parts of your website. Essential Widgets provides you with the ability to have more control over the widgets with the various customization options. This free WordPress plugin for widgets allows you to create 7 different interesting widgets on your website. All the 7 widgets provided to you comes with so many customization options and are very easy to use. So, with Essential Widgets plugin, customize the interesting widgets your way and display them anywhere you want on your website to make it more dynamic.
<ol>
<li>
EW: Archives 
The Archives widget comes with various customization options. Choose a title, limit the number of posts, select the archive type, post type, order and more with the Archives widget.
</li>
<li>
EW: Authors 
Displaying the author’s information is kind of a must-have feature if your website has multiple authors. Our new WordPress widgets plugin allows you to add Authors widget. With this widget, you can show the list of the authors on your website, the number of posts, select feed type, and more.
</li>
<li>
EW: Categories 
Essential Widgets Pro supports Categories widget. The widget provides you with various customizable options such as the title of the widget, taxonomy option, order option, number of categories to show, display as a list or none, number of posts to display, sort by option, select feed type ton display and display as text or image.
</li>
<li>
EW: Menus 
Bored with the same default menu? Our new WordPress plugin for widgets, Essential Widgets Pro supports Menus widget. With the Menus widget filled with various customization options, you can display your menus elegantly anywhere you want on your website.
</li>
<li>
EW: Pages 
Display a list of pages with the Pages widget. With various customization options being provided to you, you can showcase the pages that are more important on your website wherever you want with Essential Widgets Pro.
</li>
<li>
EW: Posts 
Essential Widgets Pro supports Posts widget. With the widget and its customizable options, you can easily display a list of posts on your website. You can add a title, select the post type, number of items to display, order, sort by, and more.
</li>
<li>
EW: Tags 
And last, but definitely not the least, the Tags widget. You can display a list of tags as cloud or list, select the order of the tags, sort by option and the number of items to be displayed. The widget also provides you with more customization options including the unit, separator, search, text type, and more.
</li>
</ol>
<h3>Translations</h3>
To translate the plugin, use translate.wordpress.org (GlotPress). You only need your WordPress.org account to join the collaborative translation project.
You can translate Essential Widgets on <a href="https://translate.wordpress.org/projects/wp-plugins/essential-widgets/" rel="nofollow ugc">translate.wordpress.org</a>.

Essential Widgets

Essential Widgets is a WordPress plugin for widgets that allows you to create and add amazing widgets with high customization option

Faceted Search vs Essential Widgets