FieldHint is an option for InputField that specifies contents to display when the input field is empty.
FindGeoLocation[] attempts to find the current geodetic location of your computer.
FrontEndDynamicExpression is a global front end option that specifies an expression to be dynamically updated whenever the front end is running.
GeneratedCell is an option for Cell that indicates whether the cell was generated from the kernel.
GridFrameMargins is an option for grids that specifies the spacing between the content of the grid and the frame surrounding it.
Modal
(Built-in Mathematica Symbol) Modal is an option to functions such as CreateDialog that specifies whether the dialog that is created should be modal to the Mathematica front end.
OutputStream["name", n] is an object that represents an output stream for functions such as Write.
OverBar
(Built-in Mathematica Symbol) OverBar[expr] displays with a bar over expr.
ParentDirectory[] gives the parent of the current working directory. ParentDirectory["dir"] gives the parent of the directory dir.
PassEventsDown is an option to EventHandler which specifies whether events handled by a particular event handler should be passed down to event handlers nested inside.