Master Crazy TetraLooks like a Master Pyraminx with circles but the piece set resembles more the Master Skewb.
Master PyraminxAn incredible creation by Katsuhiko Okamoto which later made it into a mass production.
Master XenomorphixA 4x4x4 in shape of a tetrahedron. The axis are oriented as in the Xenomorphix.
MastermorphixA higher-order Pyramorphix. A 3x3x3 transformed into the shape of a tetrahedron.
MastermorphynxLooks like a Pyraminx but is closely related to the Mastermorphix.
MegamorphixAn even higher-order Pyramorphix. This time a 4x4x4 was transformed into tetrahedral shape.
Minimorphix 2x2x2A pyramorphix in pillowed shape but with several holes in the pieces.