tmatsuur

Normally, the dropdown menu of the posts filter is a single selection. If you install this plug-in, dropdown menu of “single selection” will change to “multiple choice”. 
For example, if you select some of the categories, you will be able to view the <code>post</code> belonging to any of them in the post list page.
<h4>Some features:</h4>
<ul>
<li>Change each pull-down menu on the post list page from single selection to multiple selection.</li>
<li>Sort the post data by the last modified date and time.</li>
<li>Tags and author filters will be added to allow you to narrow down your search.</li>
</ul>
<h4>Support</h4>
<ul>
<li>Japanese – https://elearn.jp/wpman/column/posts-filter-multiselect.html</li>
</ul>
<h4>Translators</h4>
<ul>
<li>Japanese(ja) – <a href="https://12net.jp/" rel="nofollow ugc">Takenori Matsuura</a></li>
<li>Svenska(sv_SE) – Downloadable</li>
</ul>
You can send your own language pack to me.
Please contact to me.
<ul>
<li>https://12net.jp/ (ja)</li>
<li>email to takenori.matsuura[at]gmail.com</li>
<li>@tmatsuur on X(twitter).</li>
</ul>
<h4>Contributors</h4>
<ul>
<li><a href="https://12net.jp/" rel="nofollow ugc">Takenori Matsuura</a></li>
</ul>
<h3>Notice</h3>
<ul>
<li>This plugin uses <code>jQuery UI MultiSelect Widget</code> under WordPress 5.5, and uses its own script for WordPress 5.5 and later. 
link: https://github.com/ehynds/jquery-ui-multiselect-widget 
Special thanks to Eric Hynds.</li>
</ul>
<h3>Credits</h3>
This plug-in is not guaranteed though the user of WordPress can freely use this plug-in free of charge regardless of the purpose. 
The author must acknowledge the thing that the operation guarantee and the support in this plug-in use are not done at all beforehand.
<h3>Contact</h3>
email to takenori.matsuura[at]gmail.com 
twitter @tmatsuur

Posts filter multiselect

Dropdown menu in the posts filter of the single choice is changed to multi-select.

metaphorcreations

Save Time. Work Smarter. Duplicate Any Post Type with Ease.
Post Duplicator is the ultimate WordPress plugin for quickly creating exact duplicates of any post type in your WordPress site. Whether you’re working with standard posts, pages, or custom post types, this plugin makes it effortless to clone content while preserving all taxonomies, custom fields, and metadata.
Key Features:
<ul>
<li>Universal Post Type Support – Works with every post type WordPress supports, including custom post types from your favorite plugins and themes</li>
<li>Complete Data Preservation – Automatically copies all taxonomies, custom fields, metadata, and featured images</li>
<li>Bulk Duplication – Select and duplicate multiple posts at once with individual settings per post</li>
<li>Multiple Clones – Create multiple copies of a single post simultaneously (up to 50 clones)</li>
<li>Flexible Duplication Options – Customize title, slug, status, author, date, post type, and parent for each duplicate</li>
<li>Featured Image Management – Set, replace, or remove featured images directly in the duplication modal</li>
<li>Smart Defaults – Configure default settings that apply to all duplications (draft status, current user as author)</li>
<li>Post Types Configuration – Control which post types can be duplicated and which appear in the “Post Type” dropdown menu</li>
<li>Permission Control – Granular control over who can duplicate posts with role-based permissions</li>
<li>Modern Interface – Beautiful modal interface with live editing and expandable settings</li>
<li>Cross-Post Type Duplication – Convert posts to different post types during duplication</li>
<li>Hierarchical Post Support – Set parent posts for pages and hierarchical custom post types</li>
<li>One-Click Operation – Duplicate posts from the posts list, edit screen, or block editor toolbar</li>
</ul>
Perfect For:
<ul>
<li>Developers – Quickly generate test content and dummy data for development using bulk or multiple clone features</li>
<li>Content Managers – Create content templates and variations efficiently with one-click duplication</li>
<li>Bloggers – Repurpose successful posts with different angles or formats using multiple clones</li>
<li>E-commerce – Duplicate product variations and bulk duplicate similar listings across categories</li>
<li>Content Marketers – Create A/B testing variations with the multiple clones feature</li>
<li>Site Migrations – Bulk duplicate posts when restructuring or migrating content</li>
<li>Multilingual Sites – Works seamlessly with WPML and Polylang for multilingual content</li>
</ul>
What Gets Duplicated:
<ul>
<li>Post content and formatting</li>
<li>Title and slug (with customizable suffixes or full editing)</li>
<li>All custom fields and metadata</li>
<li>Categories, tags, and custom taxonomies</li>
<li>Featured images (with ability to change or remove)</li>
<li>Post format and excerpt</li>
<li>Comment and ping status</li>
<li>Menu order</li>
<li>Post parent (for hierarchical post types)</li>
</ul>
What Doesn’t Get Duplicated:
<ul>
<li>Comments (by design – prevents duplicate comment threads)</li>
<li>Post ID and GUID (new unique identifiers assigned)</li>
</ul>
How to Use:
<ol>
<li>Single Duplication: Hover over any post and click “Duplicate [Post Type]” in the row actions, or click the “Duplicate Post” button in the Gutenberg editor</li>
<li>Multiple Clones: In the duplication modal, click the copy icon to create multiple copies of a single post (up to 50 clones)</li>
<li>Bulk Duplication: Select multiple posts using checkboxes, choose “Duplicate” from the Bulk Actions dropdown, then configure each post individually</li>
<li>Customize Settings: Edit title, slug, status, author, date, post type, featured image, and parent for each duplicate</li>
<li>Configure Defaults: Go to Settings > Post Duplicator to set default status, author, date, and title/slug suffixes</li>
<li>Configure Post Types: Go to Settings > Post Duplicator > Post Types to control which post types can be duplicated and which appear in the “Post Type” dropdown menu</li>
</ol>
Default Settings:
The plugin works immediately with sensible defaults: 
* Duplicated posts are created as Drafts (prevents accidental publishing) 
* Title suffix: “Copy” 
* Slug suffix: “copy” 
* Author: Current User 
* Date: Current Time
All defaults can be customized in Settings > Post Duplicator.
Integration:
Post Duplicator works seamlessly with: 
* WPML and Polylang (multilingual support) 
* WooCommerce (excludes review counts automatically) 
* ACF (Advanced Custom Fields) – preserves all field data 
* WP Customer Area (special file duplication support) 
* All custom post types and taxonomies
Security:
<ul>
<li>Users without <code>publish_posts</code> capability cannot publish duplicates (forced to Pending)</li>
<li>Non-authors cannot duplicate unpublished posts from other users</li>
<li>Granular permission system controls who can duplicate posts</li>
<li>All data is sanitized and validated before duplication</li>
</ul>
Developer-Friendly:
Includes hooks and filters for easy customization: 
* <code>mtphr_post_duplicator_created</code> action 
* <code>mtphr_post_duplicator_meta_{$key}_enabled</code> filter 
* <code>mtphr_post_duplicator_meta_value</code> filter

Post Duplicator


so basic that i would miss this in core.



great support either!


Just great.


Much better than Yoast Post Duplicate and Page Duplicate plugins. It is a shame this plugin seems to be burried. It works better, and follows admin setting guidelines. And best of all, it does not have any obstrusive pro money swindling practices.



This is how a plugin should be made!


Perfect!

Creates functionality to duplicate any and all post types, including taxonomies & custom fields. Perfect for developers and content creators.

Posts filter multiselect vs Post Duplicator