Shape modification

Shape modification (abbreviated as Shape mod) consists of making a new cube with an existing mechanism. The most famous shape mod is the Fisher cube.
Shape mod techniques
 The main technique involves cutting the cube, filling the gaps with the paste "Epoxy sculpt" (or something else), and then sanding the surplus and finally resticker the new cube you made.
(Incomplete) List of Shape Mods
General
Platonic Solids Mods
Puzzles modded to the shape of regular tetrahedra, cubes, regular octahedra, regular dodecahera, or regular icosahedra. For example, the 2x2 shapeshifting dodecahedron is a 2x2 cube modified to be the shape of a dodecahedron.
Bipyramid Mods
Puzzles modded to the shape of bipyramids.
Fisher Cube
A Fisher cube is a cube that has been rotated 45 degrees "Fishered" internally on one axis.
A double Fisher cube is a cube that has been "Fishered" on two axes.
Barrel
A barrel mod is where a puzzle has been modified to be the shape of a cylinder.
Ghost Cube
The most common ghost cube modification is the 3x3 ghost cube. A ghost cube is made when the layers of a twisty puzzle are misaligned, then made into a shape of a cube. The 3x3 ghost cube is commonly considered the most difficult 3x3 shape mod
Ball
Any twisty puzzle can be modified into the shape of a ball.
NxNxN
Mastermorphix
A Mastermorphix is an 3x3x3 cube modified to a shape of a tetrahedron or a pillowed tetrahedron. Morphix puzzles can be made from any NxNxN cube, like the 2x2 (Pyramorphix) and the 4x4 (Megamorphix)
Windmill Cube
Axis Cube
Pyraminx and higher order Pyraminxes
Tetraminx
A Tetraminx is a Pyraminx without the tips
Skewb
Functionally identical to the Tetraminx, a Skewb is a corner turning puzzle that is a Pyraminx without tips in the shape of a cube. It was originally called the Pyraminx Cube.
Higher order Skewbs have also been made, like the Master Skewb and the Dayan 7x7 Skewb.
Ivy Cube
An Ivy Cube is a Skewb with half of the corners removed, leaving two corners diagonal to each other on each face, making for a slightly easier solve.
Megaminx
Hexaminx
A Hexaminx is a Megaminx modified to be the shape of a cube or pillowed cube. It is an edge turning puzzle, as each of its twelve edges are functionally identical to the Megaminx's twelve faces.