Gareth

This WordPress plugin displays a mini preview window on the edit post or edit page screen.
Mini Preview sits in the Page or Post tab when you are editing a page or post in WordPress.
Buttons above the preview window provide for Refresh, various display sizes, and preview in new tab.
The preview window is a fully-functional, interactive mini browser showing exactly what the page will look like, except in miniature.

Mini Preview

Displays a mini preview when a page or post is being edited.

Dogan Ucar

This plugin shows content on mobile/desktop user agents only. The ‘show_on_mobile’ and ‘show_on_desktop’ shortcodes are added with this plugin. The plugin shows a shortcode or a post/page content on mobile/desktop user agent.
Features:
<ul>
<li>shows or hides text/shortcode content only on mobile/desktop user agents</li>
</ul>

WP Show On Mobile

Shows or hides content (text or shortcodes) on mobile or desktop user agents.

Mini Preview vs WP Show On Mobile