Alien worlds

Alzarius: Alzarius, a planet in another Universe that has a unique form of evolution
Androzani Minor: Androzani Minor is a world where the drug spectrox is in high demand
Atrios: Atrios, a world that was locked into a war with Zeos
Calufrax: Calufrax, a planet that was an integral part of the Key To Time
Castrovalva: Castrovalva, a fictional world created by the Master as a trap for the Doctor
Skaro: Skaro, the radioactive home world of the dreaded Daleks, and also the peaceful Thals
Telos: Telos - one of the homes of the Cybermen
Thoros Beta: Thoros Beta, the fluorescent home of the Mentors
Varos: Varos, a former prisoner colony