1. Hath
These humanoid-fish may have turned nice after their week-long war against the humans and one may have saved Marthas life, but they were at war with the human race and they are interesting aliens, so wed like to see them again. And its not just the fans who want them back; Russell T Davies had originally planned for them to be part of the Shadow Proclamation alongside the Judoon in The Stolen Earth, but it didnt happen. However, they were included as an image seen by the Atraxi when looking at which aliens had previously posed a threat to the Earth. But, the Hath had never knowingly been to Earth, or had they? Its the perfect opportunity for a storyline: maybe they had infiltrated a government and were the brains behind one of the wars in the past? Maybe theyd staged a huge invasion and nearly changed the future of the human race? Or maybe they never met the humans, coming to Earth years before and fighting the Silurians? With so many years of Earth history to reinvent, the possibilities are endless.
Not the aliens that you would choose? Have other monsters on your mind? Leave your opinion in the comment section below.