WP Grim

The free Classic Editor & Classic Widgets plugin helps you to easily disable Gutenberg editor totally everywhere and enables Classic Editor and Classic Widgets.
Classic Editor and Classic Widgets plugin enables old-style WordPress Classic Editor for “Edit Post” with TinyMCE (WYSIWYG), Meta Boxes (Custom Fields), and others. Once activated, this plugin hides all functionality available in the new Gutenberg block editor.
<h3>What does this plugin do?</h3>
<ul>
<li>Disables the Gutenberg Editor</li>
<li>Enables WordPress Classic Editor</li>
<li>Enables Classic Widgets</li>
</ul>
Features
<ul>
<li>Disable Gutenberg totally</li>
<li>Disable Gutenberg for any post type</li>
<li>Editor Switcher</li>
<li>Choose Editor for each Post</li>
<li>Choose Default Editor</li>
<li>Choose Widgets Editor</li>
<li>Full Support Advanced Custom Fields (ACF)</li>
<li>Hide plugin menu item</li>
<li>Enable/Disable frontend Gutenberg styles</li>
<li>WooCommerce compatible</li>
<li>WPML Compatible</li>
<li>Polylang compatible</li>
</ul>
Also, you will be able to use old-style Classic Widgets under Appearance > Widgets and Appearance > Customize > Widgets. There is no need to setup any configuration.
<blockquote>
By default, this plugin hides all functionality available in the new Gutenberg block editor without setting up any extra options.
</blockquote>
<h3>Upgrade to Pro Version</h3>
<a href="https://wpgrim.com/classic-editor-and-classic-widgets-pro/?utm_source=wordpressorg&utm_medium=content&utm_campaign=cew" rel="nofollow ugc">Classic Editor and Classic Widgets PRO</a> plugin provides more additional features. Go to the Next Level with <a href="https://wpgrim.com/classic-editor-and-classic-widgets-pro/?utm_source=wordpressorg&utm_medium=content&utm_campaign=cew" rel="nofollow ugc">Pro Version</a>. Pro plugin works together with this Free Plugin and does not need any re-installation or deactivation of Free version.
Premium Features
<ul>
<li>Choose Editor for User Roles</li>
<li>Choose Editor for Custom Post Types</li>
<li>Remember Last used Editor</li>
<li>Displaying Post States</li>
<li>Exclude Posts/Pages by Autocomplete</li>
<li>Premium Support</li>
</ul>
⭐ <a href="https://wpgrim.com/classic-editor-and-classic-widgets-pro/?utm_source=wordpressorg&utm_medium=get_pro&utm_campaign=cew" rel="nofollow ugc">Get PRO Version Now</a>
<h3>More Powerful Plugins</h3>
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Developed with love by <a href="https://wpgrim.com/?utm_source=wordpressorg&utm_medium=direct&utm_campaign=cew" rel="nofollow ugc">WP Grim</a>

Classic Editor and Classic Widgets

Disables Gutenberg editor totally everywhere and enables Classic Editor and Classic Widgets.

Sumit Singh

Classic Widgets with Block-based Widgets allows you to use both widgets screens at the same time. 
Sometimes, you need to use the classic widget screen for some of the widgets without permanently disabling the block-based widgets. With this plugin, you can access the Classic Widgets screen in <code>Appearance > Classic Widgets</code> and the block-based screen at the usual place in <code>Appearance > Widgets</code>.
NOTE:- 
This plugin uses WordPress filters to create a new classic widget screen. That means it will work as long as WordPress supports the Classic Widgets screen.
<h4>Links</h4>
<ul>
<li><a href="https://github.com/5um17/classic-widgets-with-block-based-widgets" rel="nofollow ugc">GitHub repository</a></li>
</ul>

Classic Widgets with Block-based Widgets

Restore the classic widgets screen as a new menu item without replacing new block-based widgets.

Classic Editor and Classic Widgets vs Classic Widgets with Block-based Widgets