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.

Milankumar Sanandia

This plugin will WP Disable Block Editor & enable the Classic Editor and original Edit Post screen (TinyMCE, meta boxes, etc all).
<ul>
<li> Disable Block Editor on page and Enabled Old Editor.</li>
<li>Admin Option for Enabled/Disable Gutenberg Block Editor.</li>
</ul>

WP Disable Block Editor

This plugin will WP Disable Block Editor & enable the Classic Editor and original Edit Post screen (TinyMCE, meta boxes, etc all).

Relive Classic vs WP Disable Block Editor