FlexaTech

Flexa Media Folders adds a hierarchical, drag-and-drop folder tree to the WordPress Media Library. Group images, videos, documents and any other attachment into nested folders, then filter the library to a single folder with one click – in the grid view, the list view, and the media picker inside the post editor.
Folders are stored in two dedicated, indexed database tables, so your <code>wp_term*</code> tables stay clean and the tree loads fast even with thousands of files.
<h4>Features</h4>
<ul>
<li>Hierarchical folder tree – create unlimited nested folders, rename them, and reorder them by drag-and-drop.</li>
<li>Drag attachments into folders – drag an item from the Media Library straight onto a folder.</li>
<li>Works everywhere the Media Library does – the folder sidebar appears on the Media grid, the list view (<code>upload.php</code>), and the media modal in both the block editor and the Classic Editor.</li>
<li>One-click filtering – click a folder to filter the library to it, plus built-in “All files” and “Uncategorized” views.</li>
<li>Color labels – assign one of 18 colors to any folder from the right-click menu to spot it at a glance.</li>
<li>Full context menu – New Folder, Rename, Cut, Paste, Delete and Change Color, all from a right-click.</li>
<li>File counts – each folder can show how many attachments it contains (toggle in Settings).</li>
<li>Folder search – filter the folder tree as you type.</li>
<li>Settings page – choose a default folder for new uploads (none / last used / a specific folder), set the folder sort order, toggle file counts, and exclude specific post types from showing the sidebar.</li>
<li>Dark mode – the tree automatically follows your WordPress admin color scheme.</li>
<li>Accessible – full ARIA tree semantics, keyboard navigation, and visible focus styles.</li>
<li>Translation ready – every string is internationalized and a <code>.pot</code> template is bundled.</li>
<li>REST API – all screens are powered by a REST API under <code>/wp-json/flexa-mf/v1/</code>, so external integrations and your own code can read and manage folders too.</li>
<li>WP-CLI – manage folders and reset plugin data from the command line with <code>wp flexa-mf</code>.</li>
<li>Clean uninstall – a Settings danger zone (and <code>wp flexa-mf reset</code>) wipes all plugin data on demand; uninstalling the plugin drops its tables. Your media files are never touched.</li>
</ul>
<h4>Source code for compiled JavaScript and CSS</h4>
The plugin ships with minified/compiled JavaScript and CSS in <code>assets/dist/</code>. The human-readable source code for these assets is publicly available and maintained at:
https://github.com/flexatech/flexa-media-folders

Flexa Media Folders

Organize the WordPress Media Library into drag-and-drop folders with a fast React tree, color labels, and a REST API.

Yudhistira Mauris

This plugin helps you create a series of posts. It creates a new taxonomy named ‘series’ (can be modified via filter, see FAQ). There is no setting needed for this plugin. Once it is installed, assign posts you want to group as a series via post editor.
The plugin also creates a posts navigation on posts that belong to a certain series. See screenshots for the examples.

Easy Post Series

Works beautifully and doesn't have a sucking frontend design, as other similar plugins do!

Flexa Media Folders vs Easy Post Series