NormalsFunction is an option for Plot3D and related functions that specifies a function to apply to determine the effective surface normals at every point.
$DisplayFunction gives the default setting for the option DisplayFunction in graphics functions.
ExponentFunction is an option for NumberForm and related functions that determines the exponent to use in printing approximate real numbers.
StreamColorFunction is an option for StreamPlot and related functions that specifies a function to apply to determine colors along streamlines.
VectorColorFunction is an option for VectorPlot and related functions which specifies a function to apply to determine colors of field vectors drawn.
DistanceFunction is an option for functions such as Nearest that specifies the distance value to assume between any two specified points.
ColorFunction is an option for graphics functions that specifies a function to apply to determine colors of elements.
RegionFunction is an option for plotting functions that specifies the region to include in the plot drawn.
DateFunction is an option for DateListPlot that specifies how dates given as input should be converted to date lists.
Mathematica applies its strengths in calculus to the intricacies of integral transforms, with a host of original algorithms that probably now reach almost any closed form ...