Cubes

Weighted Storage Cube
These feature in both Portal and Portal 2. They are a grey/white colour with blue markings and the aperture logo in the middle of each face.

Edgeless Safety Cube
These feature in Portal 2's co-op mode.

Companion Cube
Featured in both Portal and Portal 2. They are of the same shape and colour as the Weighted Storage Cube, except they have pink colourings and have a heart in the middle of each face.

Discouragement Redirection Cubes
Brought in with Portal 2, these cubes can redirect a Thermal Discouragement Beam to any horizontal point the player wishes. On 5 faces of the cube it's a clear flat circle shape, with the sixth face having a half-sphere extruding from the cube shape, allowing the beam to enter into any face and always exit on the extruding one.