The basic form of Freeza. This form is meant to restore Freeza's energy while he isn't fighting. He might look small and weak, but don't let his appearance fool you. During this stage, Freeza also sits on a round transport which would carry him around.

The second form of Freeza basically makes him larger his size. His power level would also increase. Freeza changed into this form to fight against Chibi Gohan and Krillin. Nothing much different about this form of Freeza.

During this stage, Freeza looks like some kind of alien from outer space. Looks quite nice. Obviously, his power level and strength would experience some increase. Vegeta had quite a tough task fighting with this form of Freeza.

The most perfect and powerful form of Freeza. Has plenty of abilities and speed. He can only be defeated after Gokou managed to transform into a Super Saiyajin. A really really tough enemy for Gokou to destroy.

It is not really clear about this version of Freeza. It is said that Freeza's brother collected parts of Freeza's body and rebuilded him. It is not really known whether Cyborg Freeza is stronger than the previous version. Future Trunks just used a sword to destroy him.