StyleNameDialogSettings -> {opt -> val} is a global option that specifies the cell style displayed in the Custom Style dialog box.
SubsetEqual[x, y, ...] displays as x \[SubsetEqual] y \[SubsetEqual] ....
Subset
(Built-in Mathematica Symbol) Subset[x, y, ...] displays as x \[Subset] y \[Subset] ....
SuperDagger[expr] displays as expr^\[Dagger].
SuperMinus[expr] displays as expr^-.
SuperPlus[expr] displays as expr^+.
SupersetEqual[x, y, ...] displays as x \[SupersetEqual] y \[SupersetEqual] ....
Superset[x, y, ...] displays as x \[Superset] y \[Superset] ....
SuperStar[expr] displays as expr^*.
UnderBar[expr] displays with a bar under expr.