Buttondown Documentation
Buttondown has a built-in WYSIWYG editor (in addition to the markdown editor) that allows you to view and edit your emails in a way that resembles how they will be formatted when they are sent.
Fancy mode comes with a variety of different built-in components. To view the different options, use the toolbar at the top of the editor or type "/" on a new line.
Using Fancy mode you can include any of the following: