180° rotation rotates the piece 180 degrees. In some games, that can be actually done. It grossly depends on games.

In tetr.js, it does two clockwise SRS rotations. Therefore no new spins can be done, but it still helps with finesse.

In DTET, pressing rotate left and rotate right at the same time will rotate 180° with counter-clockwise wallkicks.

In NullpoMino, a new wallkick table is used.

In TGM3, there are two clockwise buttons. The second one is used by some players for an instant 180 rotation with clockwise wallkicks.