jomol

Simple Font Awesome Icon plugin will give you the Font Awesome Icon option in your post and page. From there you can choose the required icon and hit save. Then use the get_post_meta(‘post ID’, ‘font-awesome-icon’, true); function in the template file and you will get the class name which can be used with i tag.
Please take a look the plugin page for more details: [https://codingdom.wordpress.com/simple-font-awesome-icon/)

Simple Font Awesome Icon

Simple Font Awesome plugin will give you the option for adding Font Awesome icons for your post and pages in the form of a meta box.

Ohidul Islam

This is a simple and yet awesome plugin to enabling scroll top functionality in your site. After install the plugin you will immediately see a rocket image button on the right bottom side of you website. And you can simply customize some settings for that plugin.

SS Awesome Scroll Top

This plugin will help you to create a scroll to top button on your site

Simple Font Awesome Icon vs SS Awesome Scroll Top