Guilds, Councils, Businesses, etc.
With the 'Group Category' attribute (see 'Filter' tab at right), you can specify the type of the group.
It's helpful for developing the story of your campaign to make up the royal family. With a Hero subscription you can upload a family tree to the group you create for that.
Note that although a race or a class might be considered a group, on Scabard those are attributes of a Character, not groups.