Do you keep a simple blog, where you don’t define specific categories for your posts but simply let them all be uncategorized and use tags instead? Do you, like me, feel that all the categorizing stuff comes in the way of your content and your blog? Do you feel that keeping only one category seems superflous, but WordPress just forces you to? Then this plugin might be for you!
This plugin is mostly cosmetic, as it doesn’t change or actually remove any categories, but hides any options to change them, so all posts are in fact put in the default category (usually “Uncategorized”). This currently includes the category section on the edit pages and the “Manage categories” section on the admin pages. Published posts will not mention categories, and the Category widget has been removed.
As it doesn’t actually remove the categories or modify any files, this plugin will not affect any other plugins’ usage of categories. This means “Uncategorized” will show up on statistic pages, etc.

No Categories

Simply disables the usage of categories in your WordPress blog.

Murali

WordPress press widget to list category and subcategories of posts/custom taxonomies of custom post types.
Features
<ol>
<li>
It allows users to add custom icons for category or for subcategory or for custom taxonomies
</li>
<li>
It lists categories and subcategories in user-friendly horizontal pattern. Please refer screenshots.
</li>
<li>
Category icons can be edited/removed/update with new icons under edit category or under edit custom taxonomy admin screen
</li>
<li>
Admin settings of this widget has facility control display on/off for category icons
</li>
<li>
Admin settings of this wiget has facility to show/hide count of posts in categories
</li>
<li>
Admin settings of this widget has facility to show/hide empty categories in widget
</li>
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Title of widget can be customized in widget settings
</li>
<li>
Compatible with blocks under widgets section
</li>
</ol>
<h4>My Links</h4>
<ul>
<li><a href="https://www.muraliwebworld.com/groups/wordpress-plugins-by-muralidharan-indiacitys-com-technologies/forum/topic/category-sub-category-widget-for-wordpress-websites-using-php-javascript-jquer/" rel="nofollow ugc">Plugin homepage</a></li>
<li><a href="https://wordpress.org/plugins/push-notification-for-post-and-buddypress/" rel="ugc">Push notification plugin for WordPress,BuddyPress and for Mobile apps</a></li>
<li>Twitter @<a href="https://twitter.com/indiacitys" rel="nofollow ugc">indiacitys</a></li>
<li>Facebook <a href="https://www.facebook.com/indiacitys" rel="nofollow ugc">indiacitys</a></li>
</ul>

Category and Subcategory List Widget

This widget allows to add/update icons for category or icon for custom taxonomy. It lists Categories in horizontal menu pattern.

No Categories vs Category and Subcategory List Widget