These windows are shared in both the 2D and 3D scene editors.
Sounds
This window lists all of the sounds that you have available in the scene. Sounds can be triggered in script using the sounds collection.
Fonts
This window lists all of the fonts that you have defined in the scene. Fonts are used for text objects. To add one, click 'Add Font', or to edit a font either use the 'Edit Font' button or double click one.
For more information, please see the Fonts section.