Milan Dinić

This plugin automatically disables default block editor for all post types and all users, without any settings or options. It is very lightweight, just activate it and it works immediately.
And it’s on <a href="https://github.com/dimadin/disable-block-editor" rel="nofollow ugc">GitHub</a>.

Disable Block Editor

Disable block editor for all post types and all users.

Pieter Bos

gschoppe

<blockquote>
GDPR-compliant: does not collect any user data
</blockquote>
The free “Classic Editor +” plugin is targeted at everyone who does not want to use the WP Block Editor (Gutenberg), introduced in WordPress 5.0. Install it now on sites and the UX remains the same as you are used to without redundant styling being added to the frontend of your site!
What’s New: 
Removes WP Patterns
This plugin simply disables the WP Block Editor, removes any and all styling from both front- and backend and disables the block editor for widgets too.
And if WooCommerce and/or WPML are installed on the site, “Classic Editor +” removes the block styles of those plugins too.
There are no Settings, it simply does what it says on the label.
Therefore I highly recommend installing this “Classic Editor +” plugin.
I support this plugin exclusively through <a href="https://github.com/senlin/classic-editor-addon/issues" rel="nofollow ugc">Github</a>. Therefore, if you have any questions, need help and/or want to make a feature request, please open an issue here. You can also browse through open and closed issues to find what you are looking for and perhaps even help others.
Thanks for your understanding and cooperation.
If you like the “Classic Editor +” plugin, please consider leaving a <a href="https://wordpress.org/support/view/plugin-reviews/classic-editor-addon?rate=5#postform" rel="ugc">review</a>. Thanks!
“Classic Editor +” by <a href="https://so-wp.com/plugin/classic-editor-addon" rel="nofollow ugc">Pieter Bos</a> and <a href="https://gschoppe.com" rel="nofollow ugc">Greg Schoppe</a>.

Classic Editor +

The "Classic Editor +" plugin disables the block editor, removes enqueued scripts/styles and brings back classic Widgets.

Disable Block Editor vs Classic Editor +