The user guide and codex documents these features, though there is no definitive list (maybe we’ll add that as a todo).
But in the Visual Editor has the Style dropdown and the Green buttons which gives quick access to css styles.
Boxes and buttons are implemented with css styles nor shortcodes (which is a crime other themes may commit but not here). These styles are inserted by the buttons or by the style dropdown selector in the visual editor.
The only shortcodes are for inserting event lists or the show posts/pages code. Again a quick insert button is available in the visual editor, though these are both fully documented in the codex.