ShowAutoStyles is an option for Cell that specifies whether styles that are specified to be automatically used for various syntactic and other constructs should be shown.
ShowCellLabel is an option for Cell that specifies whether to display the label for a cell.
SubMinus[expr] displays as expr_-.
SubPlus
(Built-in Mathematica Symbol) SubPlus[expr] displays as expr_+.
SyntaxQ
(Built-in Mathematica Symbol) SyntaxQ["string"] returns True if the string corresponds to syntactically correct input for a single Mathematica expression, and returns False otherwise.
TransferFunctionCancel[tf] cancels common poles and zeros in the TransferFunctionModel object tf.TransferFunctionCancel[tf, crit] cancels only common pole-zero pairs e_i for ...
VerifyConvergence is an option to Sum, NSum, and similar functions that specifies whether convergence checking should be done.
ViewRange is an option for Graphics3D and related functions which specifies the range of distances from the view point to be included in displaying a three-dimensional scene.
ZeroTest is an option to various linear algebra functions that gives a function to use in testing whether symbolic expressions should be treated as zero.
$ExportFormats gives a list of export formats currently supported in your Mathematica system.