Fastmover

A simple drop down selection meta box on a post edit page will allow you to specify default, HTTP or HTTPS. Default will allow both HTTP and HTTPS protocols.

Protocol Enforcer

This plugin allows a user to specify a post to only be viewed over HTTP or HTTPS.

phikai

Forces the front end of your WordPress site to HTTP when you only want the Admin over HTTPS
Please help by reporting any bugs/feature request at the link below.
Bugs:
<ul>
<li>Report at: <a href="https://gitlab.com/phikai/wordpress-force-http/issues" rel="nofollow ugc">Issue Tracker</a></li>
</ul>
Questions/Comments:
<ul>
<li>http://www.kaiarmstrong.com/contact/</li>
</ul>

WordPress Force HTTP

Forces the front end of your WordPress site to HTTP when you only want the Admin over HTTPS

Protocol Enforcer vs WordPress Force HTTP