Circle 1x2x3A 1x2x3 with circles in the small faces. This doesn't change the puzzle but looks fascinating.
Circle DinoCould be treated as a slices only variant of a higher order skewb.
Circle SkewbA corner turning hexahedron with three logical layers. It looks as if "circle moves" were added to the skewb.
Circle X CubeA new contour cut variant of the Redi Cube and Lucky Clover Cube.
Clockwork 4x4x4A 4x4x4 with all layers of one dimension linked into one coordinated movement.
Clover Chop ExtremeA puzzle with hybrid axis system which available turns are reduced to those available on one side with the edge turns doubled.
Coin Chest PuzzleModified version of Treasure Chest to allow coins be placed into it. One face was replaced and two corners were cut into.
Collider CubeA face turning tetrakis hexahedron in the shape of a cube.