Slim 2x3x3A 2x3x3 whichs height is less than one fourth of its width.
Slim 3x3x5A flat 3x3x5, based on a Russian domino.
Slim 3x3x6A 3x3x6 cuboid with less height than width.
Slim CubeA 3x3x3 forced into the dimensions of a Floppy cube and thereby changing its solving properties.
Slim Horror CubeSlim "Horror" Bump Cube (Mirror Blocks) has two layers of equal but unproportional size.
Spalt CubeA 2x2x4 turned into a pattern and redesigned into something akin a bandaged 2x4x4.
Special 2x2x3Looks like a 2x2x3 but it is an enhanced hexagonal prism.
Specter CubeA fully functional 3x4x4 built by Mr. Watanabe and presented by Mr. Okamoto
Spin BlockA Fidget Spinner pretending to be a Floppy cube but it is just a 1x1x3.
Split 1x2x3 IIIA 1x2x3 with split edges. The concept of Square-1 turned upside down.