‘We call this a “general styles” page’
Brian Warren, writing for Typekit:
Make sure you design how bolds and italics look in a paragraph, as well as lists, blockquotes, and all the common styles that will show up in a page.
You can include tables, images, captions, and even form elements. Planning ahead for the styles you might need in the future helps you build a more complete typographic system and avoid any surprises.