Use different collection types for your purposes:
Local - Stored in *...ProjectFolder*\Saved\Collections
Does not use Revision Control.
Private - Stored in *...ProjectFolder*\Content\Developers\*UserName*\Collections
Uses Revision Control. Only you will have access to the collection.
Shared - Stored in *...ProjectFolder*\Content\Collections
Uses Revision Control. The collection will be available to all project developers.
Collections that use Revision Control cannot be nested within a collection of type Local.
Click on the icon with the "+" sign.
Select the desired collection type and enter a name for the collection. Collection names must be unique.
Click on the collection name to open the collection preview.
You can create a complex hierarchy of collections for your needs.
Add assets to the collection by simply dragging them from the Content Browser to the collection preview.
Right-click on an asset in the collection preview window to bring up the context menu.
You can focus the Content Browser on the selected asset.
You can remove the selected asset from the collection.
Right-click on the collection name to bring up the context menu.
You can Rename and Delete the collection.
You can Save, Refresh and Update collections using Revision Control.
Using the collection context menu, you can create a separate window with a collection preview and place it anywhere in the editor interface.
The main widget with collections can be moved along the screen border to choose the most convenient location.