JT-BallA combination of the tricylinder 3x3x3, cornerless cube and an unusual stickering scheme.
Jumbo Magic CubeThis is huge (penny to show relative size). It is larger than a 4x4x4 or 5x5x5.
Justice League CubeA 3x3x3 covered with symbols from the heroes of the DC franchise of the same name.
JVC Rubik's CubeA nicely packaged promotional Rubik's Cube featuring JVC and a soccer theme.
K.O. LabyrinthA maze combined with a traditional 3x3x3 in shape of a big sphere with hollow pieces. The package reads "The ultimate 3D Puzzle and maze"
KakuroA 3x3x3 stickered with a japanese number riddle.
Keel kubeA rounded prism with a penrose triangle as base.
Ken KenA 3x3x3 stickered with a japanese number riddle.
Keroppi Key ChainThis key chain puzzle features the popular Sanrio character Keroppi.