You get an ObjectsTool in Morphic if you choose objects (Cmd-O) from the TheWorldMenu. You can also click on the "Widgets" tab on the bottom right-hand side of the Squeak desktop, click on the "Object Catalog" icon and drag onto the desktop.
You may drag out Morphs from it to populate your Morphic World.
Some Morphs available from the ObjectsTool:
How to add your own Morphic subclass to the ObjectsTool
Add a class side method #descriptionForPartsBin (browse implementors). This method returns a description of how to create and present a new morph. If you want several different entries in the Objects Tool, you can use #supplementaryPartsDescriptions.