LibraryFunction[args] represents a function that has been loaded from a Wolfram Library.
LocatorAutoCreate is an option for LocatorPane, Manipulate, and related functions that specifies whether new locators should be created when clicking away from existing ...
MouseAnnotation[] gives any mouse annotation associated with the expression at the current mouse position.
MultilineFunction is an option for UnderscriptBox and related box objects that specifies what to do when the contents of a box object are too long to fit on one line.
NumberSigns is an option for NumberForm and related functions which gives strings to use as signs for negative and positive numbers.
Operate
(Built-in Mathematica Symbol) Operate[p, f[x, y]] gives p[f][x, y]. Operate[p, expr, n] applies p at level n in the head of expr.
PlaceholderReplace is an option to Paste that determines whether to replace a selection placeholder with the selected contents.
PlotRangeClipping is an option for graphics functions that specifies whether graphics objects should be clipped at the edge of the region defined by PlotRange, or should be ...
PrintAction is an option for notebooks that specifies the action taken when a Print[] command is evaluated by the kernel.
SamplingPeriod is an option that specifies the sampling period of control system models.