DefaultStyleDefinitions is a global option that specifies the default stylesheet for all new notebooks.
FormBoxOptions -> {opt_1 -> val_1, opt_2 -> val_2} is an option for cells that specifies settings for FormBox objects within the cell.
GraphHighlightStyle is an option to Graph and related objects that specifies styles to use for highlighted graph elements.
IncludeFileExtension is an option for notebooks that specifies whether the suffix ".nb" is automatically appended to a notebook's name when it is first saved.
InputAliases is an option for cells and notebooks which specifies additional Esc\[ThinSpace]name\[ThinSpace]Esc aliases to be allowed on input.
InputAutoReplacements is an option for cells and notebooks which specifies strings of characters that should be replaced immediately on input.
PrintAction is an option for notebooks that specifies the action taken when a Print[] command is evaluated by the kernel.
PrintingStartingPageNumber is an option for notebooks that specifies what number to assign to the first page of a notebook when printed.
StyleDefinitions is an option for notebooks that gives definitions for the styles that can be used in a notebook.
ViewVertical is an option for Graphics3D and related functions which specifies what direction in scaled coordinates should be vertical in the final image.