You can select a group of Favorites and either tag them as a group, or copy them as a group to another account.
To select a Favorite, hover over it. A checkbox will appear in the top right.
Click the checkbox to select the favorite. The title of the app will also be selected.
When you select a favorite, a bar appears which allows you to manage the selected favorites.
Use the "Tag selected favorites" to tag all the favorites at once.
Use the "Copy to account group" section to copy the selected favorites to another group you have access to.