I’ve attached a document that should have all the standard text styles in it.
You should have these by default on new documents so I don’t know how yours have gone missing.
You can import the text styles from the hamburger menu in the Text Frame Panel.
As for the Group Styles, I don’t know what they are supposed to be used for. I can inherit things from a non-group text style so I don’t know why I would do otherwise, but maybe I’m missing out on some good functionality.
blank-document-with-standard-text-styles.afpub