SubsetEqual[x, y, ...] displays as x \[SubsetEqual] y \[SubsetEqual] ....
Subset
(Built-in Mathematica Symbol) Subset[x, y, ...] displays as x \[Subset] y \[Subset] ....
SucceedsEqual[x, y, ...] displays as x \[SucceedsEqual] y \[SucceedsEqual] ....
Succeeds[x, y, ...] displays as x \[Succeeds] y \[Succeeds] ....
SucceedsSlantEqual[x, y, ...] displays as x \[SucceedsSlantEqual] y \[SucceedsSlantEqual] ....
SucceedsTilde[x, y, ...] displays as x \[SucceedsTilde] y \[SucceedsTilde] ....
SuchThat[x, y] displays as x \[SuchThat] y.
SupersetEqual[x, y, ...] displays as x \[SupersetEqual] y \[SupersetEqual] ....
Superset[x, y, ...] displays as x \[Superset] y \[Superset] ....
SuzukiGroupSuz[] represents the sporadic simple Suzuki group Suz.