ostin654

After installing Dean’s FCKEditor for WordPress you will need to apply wpautop() to all posts and pages
После установки Dean’s FCKEditor for WordPress необходимо выполнить wpautop() для всех записей блога и страниц

Make Autop

Allows you to apply wpautop() function to all posts and pages

MarcusPope

J-Ro

Azragh

This plugin preserves the user-generated HTML markup in the TinyMCE editor. Unlike other plugins this one allows developers to work in the HTML tab AND end-users to work in the WYSIWYG Visual tab at the same time! No longer will your HTML markup be completely munged into an unrecognizable form when you switch between those tabs. And you don’t have to hang your users/editors out to dry when you hand off the project with a disabled Visual tab.
<h4>IMPORTANT: Please read the installation instructions carefully. If you have existing content it will not render properly after activating this plugin until you use the Fix It Tools.</h4>
(One user didn’t read or follow these steps and panicked thinking I ruined their website.)
It also supports HTML5 Block Anchor tags in addition to other HTML5 elements, something that is currently not supported in WordPress via any existing plugins.

Preserved HTML Editor Markup Plus

Preserves HTML and developer edits in HTML AND WYSIWYG tab.  Supports inline scripts/css, JavaScript code blocks and HTML5 content editing

Make Autop vs Preserved HTML Editor Markup Plus