Webamator

YouTube iframe embeds often load many unnecessary resources, which slows down your page. YEP: Optimize YouTube Embeds is a lightweight WordPress plugin that replaces YouTube iframes with a clickable preview image. 
The actual video loads only when the user clicks the play button, improving page load times and reducing initial page size.
<h3>External services</h3>
This plugin uses the external YouTube thumbnail service (https://i.ytimg.com) to display preview images of YouTube videos. 
When a page with a YouTube embed is loaded, the plugin requests the thumbnail image directly from YouTube servers. 
No personal data is sent from your site to YouTube, only the video ID (already public in the YouTube URL).
Privacy Policy: https://policies.google.com/privacy 
Terms of Service: https://www.youtube.com/t/terms

YEP: Optimize YouTube Embeds

Short Description: Load YouTube videos faster by replacing iframes with a preview image; the video plays only when clicked play.

WonderPlugin

Wonder Video Embed
WonderPlugin Video Embed is an easy and powerful way to add videos to your WordPress. You can embed your video to the sidebar widget, WordPress posts and pages. It supports YouTube, Vimeo, Wistia and self-hosted MP4/WebM videos. The video player is fully responsive and works on iPhone, iPad, Android, Chrome, Firefox, Safari, Opera, Internet Explorer and Microsoft Edge.
Features
<ul>
<li>Support YouTube, Vimeo, Wistia, iFrame and self-hosted MP4/WebM videos</li>
<li>Work on mobile, tablets and all major web browsers, including iPhone, iPad, Android, Firefox, Safari, Chrome, Opera, Internet Explorer and Edge</li>
<li>Fully responsive</li>
<li>Insert videos to sidebar widget</li>
<li>Insert videos into pages and posts</li>
<li>Play in lightbox popup (working together with our premium plugin <a href="https://www.wonderplugin.com/wordpress-lightbox/" rel="nofollow ugc">Wonder Lightbox</a></li>
<li>Auto lightbox popup on page load</li>
<li>Auto close video popup when the video ends (support YouTube, Vimeo and MP4/WebM videos)</li>
</ul>
Use in Gutenberg Editor
<a href="https://www.wonderplugin.com/wordpress-video-embed-plugin/how-to-use-wonderplugin-video-embed-in-gutenberg-editor/" rel="nofollow ugc">How to use the plugin in the Gutenberg editor</a>
Quick Start Video
<iframe loading="lazy" title="How to insert Videos into a WordPress Page/Post" width="750" height="422" src="https://www.youtube.com/embed/ycMBLd1T7bw?feature=oembed" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
<iframe loading="lazy" title="How to insert videos into WordPress Widget" width="750" height="422" src="https://www.youtube.com/embed/mV0ME4GQDEA?feature=oembed" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>

Wonder Video Embed

Embed MP4, Youtube, Vimeo, Wistia videos to the sidebar widget, WordPress posts and pages.

YEP: Optimize YouTube Embeds vs Wonder Video Embed