Heaven's CuboidThe concept of the Ghost Cube applied to a 3x3x4 with the offset layers along the 4-layered axis.
Hell's CuboidThe concept of the Ghost Cube applied to a 3x3x4 with the offset layers along the 3-layered axis.
Holey X-BlockA Holey Skewb (aka Void Skewb) that has been extended on two sides.
Hollow 1x2x2Probably the most minimalistic twisty puzzle although by far not the most trivial to make.
i! cubeCombines the concept of the I-Cube with the Bump Cube.
I-Cube Bumpoid 4x5x5A 5x5x5 cube "bumped," the top two layers glued, then 3D printed extentions added to the sides.