Nhat Huynh Van

<blockquote>
It’s hard to change if you love something!
</blockquote>
I’ve been using the original/classic editor for over 10 years now and the experience has always been 100% smooth and the original Visual Editor was awesome. 
I like to keep that to myself and I’m sure there are some people like me who like the classic, easy to use and simple thing.
This plugin disables the new Gutenberg Editor (Block Editor) and replaces it with the Classic Editor. 
The Disable Gutenberg plugin restores the classic (original) WordPress editor and the “Edit Post” screen.
Features
<ul>
<li>Classic Editor</li>
<li>Disable Block Widgets and restore Classic Widgets</li>
<li>Enable/disable frontend Gutenberg stylesheet</li>
</ul>
<blockquote>
Works same as Classic Editor plugin, but lightweight, simple and super fast
</blockquote>
Easy to Use
<ul>
<li>Super simple</li>
<li>Clean, secure code</li>
<li>Built with the WordPress API</li>
<li>Lightweight, fast and flexible</li>
<li>Works great with other WordPress plugins</li>
<li>Focused on flexibility, performance, and security</li>
</ul>

Relive Classic

Plugin Relive Classic is help you use editor, widgets in classic style and disable Gutenberg.

Ayon M

This is a lightweight Classic Editor plugin that gives you complete control over when to use the Classic Editor vs the Block Editor (Gutenberg). Despite the introduction of Gutenberg, a brand new block editor with WordPress 5.x, many users still prefer the Classic Editor due to its compatibility and ease of use.
What does this plugin do?
<ul>
<li>Disables the Gutenberg Block Editor (with granular control)</li>
<li>Reverts back to the Classic WordPress Editor</li>
<li>Reverts to Classic Widgets section</li>
<li>Configure which post types use Classic Editor</li>
<li>Configure which user roles use Classic Editor</li>
<li>Simple mode for quick setup or Advanced mode for granular control</li>
<li>Modern, user-friendly settings interface</li>
</ul>
How to use this plugin?
<ul>
<li>Simple Mode: Just activate the plugin and it works immediately (default)</li>
<li>Advanced Mode: Enable “Advanced Settings” to configure per post type and user role</li>
</ul>

Enable Classic Editor & Widgets

A simple & lightweight plugin to enable the classic editor on WordPress with advanced configuration options.

Relive Classic vs Enable Classic Editor & Widgets