aykanburcak

This plugin adds a Gutenberg block container to your site so that you can add YouTube videos as a background to it. YouTube video backgrounds is a single block that nests other blocks.

Simple Video Background Block

The plugin that allows to add YouTube video backgrounds.

tommygeorge

Super Simple jQuery Parallax Background enables a parallax effect with your theme’s background image. Just set a background image in your theme’s “customize” options (optionally setting it to “fixed” position) and activate this plugin. Done. “It just works.”
It relies on jQuery, which comes with WordPress and is probably built into your theme. Tested and works with the “Twenty Twelve” theme out of the box.
Looks best with seamlessly-tiling background images.

Super Simple jQuery Parallax Background

For themes with background images, creates a parallax effect when scrolling. Super simple; no configuration. Just works.

Simple Video Background Block vs Super Simple jQuery Parallax Background