A Collection object is a predefined object that contains (is a parent object for) all instances of a similar object.The following is a list of collection objects:
Contains all documents open in the current AutoCAD session.
Contains all graphical objects (entities) in model space.
Contains all graphical objects (entities) in the active paper space layout.
Contains all entities within a specific block definition.
Contains all blocks in the drawing.
Contains all dictionaries in the drawing.
Contains all dimension styles in the drawing.
Contains all items in the File Dependency List.
Contains all groups in the drawing.
Contains all hyperlinks for a given entity.
Contains all layers in the drawing.
Contains all layouts in the drawing.
Contains all linetypes in the drawing.
Contains all menus currently displayed in AutoCAD.
Contains all menus and toolbars currently loaded in AutoCAD.
Contains named plot settings in the drawing.
Contains all registered applications in the drawing.
Contains all selection sets in the drawing.
Contains all text styles in the drawing.
Contains all user coordinate systems (UCS's) in the drawing.
Contains all views in the drawing.
Contains all viewports in the drawing.