Simple Author Box for WordPress now support Discord icon. You can find it starting from version 2.3.18 both with the free and the premium version.

You can download the free version here: https://wordpress.org/plugins/simple-author-box/

If you’re interested in a WordPress plugin with support for co-author (multiple authors) and guest authors and many other interesting options, please have a look at the premium version: https://wpauthorbox.com