Lists allow you to group items in your collection together and are free-form, i.e. you can group items however you like.
You can find the List Management by going to My Stuff > List Management
In List Management you can create, edit, mark as private or delete new Lists -
To add a new List use the button on the top right -
Adding Collectibles to your Lists
You can add items to your lists when you first add them to your Collection (using the Long Form) or when editing an item or from Collection Management using the Actions button
If you want to add a lot of Items at the same you can use the Bulk Actions feature in Collection Management -
You can find items in your Collection that are not yet in any List by using the"None" option in the List Filter on the right-hand side -
Just select the List you want to share, it will show as underlined as here in this example -
Copy the URL and send it to the party you want to share with (or post it in a post or document).