Is there a simple way to add Font Awesome icons in a selectfield to Kirby 3?
I personally don’t know of any plugin for Kirby 3 yet. There were some solutions for Kirby 2: Custom field - Font Awesome Icons
You could however simply use a json API for the select options: https://getkirby.com/docs/reference/panel/fields/select#options-via-api
Googling “fontawesome json” will surely get you a nice list of the icon names for your version.
Everything else, like displaying the icon after selecting it, requires a custom field.