Weighted Storage Cube
The Weighted Storage Cube was first introduced in Portal, and remains prevalent in Portal 2. In Portal 2 however, the cube is given a blue ring in the center instead of a blue cross, and can turn yellow when placed upon a Super Button.
Weighted Companion Cube
The Weighted Companion Cube was first introduced in Portal, and remains prevalent in Portal 2. Similar to the Weighted Storage Cube, the Companion Cube possesses a different design in Portal 2. The Cube functions in the same way as a Weighted Storage Cube, being differentiated to encourage test subjects to feel attached to the Cube. A feature to the new Companion Cube in Portal 2 is that it is able to sing.
Edgeless Safety Cube
The Edgeless Safety Cube was officially introduced in Portal 2, where it is used only in the co-op campaign. However, it also appears once in the single-player campaign as garbage. The entire name is given out of irony, however it still retains the coloring scheme and patterns present in the designs of the other cubes.
The Edgeless Safety Cube did have an appearance in a Portal Challenge Map and a Portal: Still Alive Map, however it did not have a notable name and also did not have an accompanying receptacle, thus is not widely considered to have its first appearance until Portal 2.
This Item appears in Chapter 2 chamber 6, while GLaDOS is cleaning out the cube dispenser, where 2 of them fall out amongst other garbage.
Discouragement Redirection Cube
The Discouragement Redirection Cube was introduced in Portal 2. Its main purpose is to redirect the Thermal Discouragement Beam to other places or through portals if necessary. However, the cube has a second use as a Weighted Storage Cube, as it can be used to activate the Heavy-Duty Super Button.
Frankenturrets are Sentry Turret and Weighted Storage Cube hybrids created by Wheatley in order to complete test chambers when he had no test subjects. They are present in the single-player chapters, The Itch and The Part Where He Kills You.
Frankenturrets do not speak, and instead emits incomprehensible chirping sounds. They act as Wheatley's replacement for Storage Cubes, but their behavior is different. Frankenturrets will hop around aimlessly while not placed on a button. When picked up by Chell or put on a button, they retract their legs inside their cubes. If they fall over on their sides or upside down, they will wave their legs trying to get up.
In the Pre-1 chamber of chapter 8, Potato-GLaDOS will attempt to stun Wheatley with a paradox that he fails to understand. It can be noted that when Potato-GLaDOS speaks the paradox, all of the Frankenturrets in the room will fold up their legs, twitch violently, emit electrical sparks and have their pupils rapidly change size, which indicates they are, at least, partially capable of understanding words.
The Scalable Cube is exclusively featured in the Portal 2 Sixense DLC Test Chambers. The only way to scale the Cube is with the Razer Hydra Controllers, a feature supported by the Portal Gun in the DLC. The size of the Cube changes simultaneously with its mass. The Scalable Cube can be used to build bridges between gaps or to crush Turrets.
The Contraption Cube is exclusively featured in the Portal 2 - Educational Version Puzzle Creator. It has adjustable mass, friction and elasticity. The minimum mass is 1kg, maximum mass is 85kg. There are 5 levels for friction: frictionless, slippery, normal, sticky and very sticky. There are also 5 levels for elasticity: no rebound, slight rebound, normal, bouncy, very bouncy. The default settings for the Contraption Cube are 40kg, frictionless, and no rebound. Different settings cause the cube to take on slightly different appearances. It has its own button, the Contraption Cube Receptacle.
The Skull cube is a cube with a crudely drawn skull on it, and only appears in Portal: Still Alive.
They are connected to buttons that fizzle the cube when pressed.