Vitalii Rizo

Loading of JavaScript resources should be done asynchronously, in a non-blocking manner, so the load time of your webpage will not be affected (it would not be delayed by render-blocking JavaScript). But using of deferring or async loading of jQuery causes lots of problems with jQuery plugins. This plugin replaces default WordPress’s JS loader with a special jQuery loader (jQl), that’s why there are no any errors with jQuery plugins.
It’s highly recommended to use any concatenate plugin, e.g., Fast Velocity Minify or WP Fastest Cache. Please, do not add jQuery to the ignore list, because this plugin fixes “undefined jQuery” errors on the console log. Also, it is allowed to use defer or async parsing of JS files.
It requires WordPress 4.1 and newer.
It is available in English and Russian.

jQuery & Plugins Asynchronous Loader

This plugin asynchronously loads jQuery and its plugins without "jQuery is undefined" errors.

Adnan

WPBrigade

Inline JS block helps in adding above the fold JS or for your Advanced customization needs.
Note: JS Script tags are necessary to run the JS Code. So add these tags to compile your code.

Inline JS Block for Gutenberg

Inline JS block helps in adding above the fold JS or for your Advanced customization needs.

jQuery & Plugins Asynchronous Loader vs Inline JS Block for Gutenberg