SNAKE MEN / REPTONS

Snake Men are a species of humanoid saurians who developed as an agressive spacefaring civilisation. They invaded planet Eternia in the distant past and were defeated. There now remains only a handful of them and most of them have devolved into the more peaceful reptons.

ETERNIANS / ETHERIANS

Eternians and etherians are humanoid species ressembling normal humans and genetically compatible with them. It has been hinted that they might be descendants from humans of the future.
They are the dominant lifeform on both Eternia and Etheria, sister planets orbiting a yellow sun whose exact spatial location remains unknown, although it has been hinted that it might be inside a space-time singularity, wether a junction of alternate universes or a pocket dimension caused by the presence, for a long time, of the Starseed at its core, a spark left over from the creation of the universe.
Some kind of wormhole exists linking Eternia's system to the Solar system and two space expedition have been known to fall through it.
Eternia is quite earthlike and has large bodies of water. It is separated into two very distinctive regions, the light and a dark hemisphere.
Eternians developped a technologically very advanced civilisation that has, for msot of it, regressed to a much more barbaristic state. Although some very advanced technology is still in use on the planet, it cohabits with magical science.
Apart from the dominant humanoid lifeform, the planet features an incredible variety of lifeforms, from monsters to sentient races.

PYROVILE

Planet of origin: Pyrovilia

The Pyrovile is a alien species that evolved on Pyrovilia. They are made of stone held together by living magma. They had developed space travel more than 2000 years ago when they lost their homeworld. They are very fragile to water exposition since it causes their magma to cool.
One of their survivor ships crashlanded in Italy, shattering them into dust. In 62 AD an earthquake which reawakened mount Vesuvius re-awakened them, and under gaseous form, they started possessing human hosts and planned to terraform Earth to make it more like Pyrovilia through the use of an energy conversion matrix. On Earth, they assumed a shape resembling that of giant roman gladiators but it remains unknown if this is their true form or if this likeliness was linked to the possession of humans. They were all destroyed in the AD 79 eruption of Mount Vesuvius.

ADIPOSE

Adipose are a sentient bidpedal species that developed a space faring civilisation whose body is mainly composed of fat.

Their natural mean of reproduction remains unknown but when their breeding world became unfit for use in the early 21st century, they enlisted the service of alien agent to have their birthing matrix implanted in humans through ingestion. Each matrix was building an adipose baby from large fat deposits contained in their overwieght human hosts. The baby was then extracting itself from fat mass with minimal harm done to the host. Adipose babies are notorious for their precocious motor autonomy. As soon as they are born they are able to walk with an overall good sense of orientation and purpose.
Source: Doctor Who "Partners in Crime"

CALAMARI FLY

The Calamari fly is an omnivorous nomadic animal species that lives in swarm. The swarm's path seems random and based on external olfactory inputs for what specialists have been able to determine. An adult fly can come up to a lenght of about 30 centimeters.

MIDOMAR

An 5th cm high alien species whose members can travel through radio waves and can recorporate themselves by draining energy from radio receiver devices.
Source: Torchwood website

ARKANS

Almost liquid alien species which developed a space fairing civilisation who visited the solar system in the early 21th century. They cannot survive in an Earht type envrionment.
Source: Torchwood, "Cyberwoman"

BESSAN

A winged species that was conquered and destroyed by the Krillitane.
Source: Doctor Who, "School Reunion"

SEX MONSTER / SEX GAS

A gaseous alien parasite that feeds on orgasmic energy. Composed of vorax and ceranium gases, Earth's atmosphere is poisonous to the alien, so it needs to take a human host to survive for prolonged periods. It vies for control with its host, causing physiological changes that eventually cause the host's internal organs to explode.

The alien also makes its host secrete a blend of ultra-powerful pheromones that cause tremendous sexual attraction in those around it for the purposes of feeding. Coupling with the host is fatal, causing the host's partner to disintegrate into a pile of dust at climax and allowing the alien to absorb the energy from the orgasm.

A specimen came to Earth in a meteorite in the early 21st century and landed near Cardif. Although the technological level of the entitiy is unknown, it refered to the meteorite as his ship and said it came to Earth by design, so it has some knowledge of interstellar scale and has the ability to manoeuver through space in a container of some sort.

Source: Torchwood "Day One"

DOGONS

The Dogons are a space faring reptilian species with thirteen eyes, each of which grant them especially enhanced perceptions in various respects. A Dogon ship crashed near the british town of Cardif in the early 21st century and some dead specimen were dissected by human scientists.
Source: Torchwood "Random Shoes"

EXXILONS

Planet of Origin: Exxilon

A highly advanced civilisation of bald silicon-based humanoids with bulbous eyes and bark-like glowing skin, the Exxilon visited Earth and were mistaken for space gods in ancient Peru. They created the City, a huge complex imbued with artificial intelligence that turned on them, either killing them or casting them out. The surviving Exxilons then either reverted to stone-age savagery, worshipping the city and offering sacrifices to it; or fled the city and the savages but were persecuted by their peers and driven to the planet's lower levels. The mineral parrinium, the only antidote to the disease known as the space plague, was found only on Exxilon.

Source: Doctor Who "Death to the Daleks"

ARGOLINS

Planet of Origin: Argolis

Argolins are yellow skinned humanoid nhabitants of Argolis who developed an nascent interstellar civilisation until 2250, when after a 20-minute nuclear war with the Foamasi, their planet was tunred into a nuclear wasteland and the few surviving Argolins became sterile. The radiation also slowed down their metabolic rate, making them appear ageless for a long period of time, until they suddenly withered away in a matter of hours. The surviving Argolins rebuilt their civilisation around services to other civilisations and became leisure providers. They attempted to renew their race through cloning but with poor results until, in 2290, when they were on the verge of bankrupty, alien input allowed them to perfect a Tachyon Recreation Generator to rejuvenate their race.
Source: Doctor Who “The Leisure Hive”

ARCTURUS

Planet or origin: It is not known if the name of the species related to the star known to humans as Arcturus.
The arcturus are non humanoid multi-strand organisms with a roughly skull shaped mass with two eyes at its center. They cannot survive in Earth-like environments, unless immersed in a container filled with their native life fluids. They often have such containers equipped with traction unit to move around on alien worlds. They have developed an advanced space faring civilisation and, in the future, will be members of the same Federation as Earth and Alpha Centauri.
Source: Doctor Who, 'The Curse of Peladon", "The Beast of Peladon"

SIGNORTIYU

A sentient species that existed some 3 billions years ago and was wiped out by the the Sou(ou) shi after the Aveletians but prior to their visit to Venus.
Source: Doctor Who Novel "Venusian Lullaby"

PHILOTIRIANS

A sentient species that existed some 3 billions years ago and was wiped out by the the Sou(ou) shi prior to their visit to Venus.
Source: Doctor Who Novel "Venusian Lullaby"

GOWENN

A sentient species that existed some 3 billions years ago and was wiped out by the the Sou(ou) shi prior to their visit to Venus.
Source: Doctor Who Novel "Venusian Lullaby"

AVELETIANS

Planet of Origin: Aveletia
A sentient species that existed some 3 billions years ago and was wiped out by the the Sou(ou) shi prior to their visit to Venus. The Sou(ou) Shi ate all the Aveletians and used their detritus to fertilize another world (whose identity remains undetermined) where life developed based on the Aveletian's genetic code.
Source: Doctor Who Novel "Venusian Lullaby"

THE PEOPLE / THE ALSO PEOPLE

Planet of origin: Worldsphere
The People are an ancient highly advanced utopian society probably born of several alien species, living in a Dyson Sphere called the Worldsphere.
They appear to be a combination of biological and artificial beings; having integrating their technology into their very essence, being able to switch their gender, forms or their minds at will, being able to become a humanoid lifeform or part of a spaceship. They do not appear to have developped time travel yet.
Source: Doctor Who "The Also People" novel by Ben Aaronovitch

GREY MAN'S RACE

Humanoid species that was among the first sentient planetbound lifeform of the universe. The developped an advanced civilisation. They are said to be partly responsible for instillating the good versus evil dualism in the structure of life in the universe. When they became exticnt or disappeared remains unknown but one of their survivors devoted his existence to trying to find a way to weaken this dualism.
Source: Doctor Who, "Falls the Shadow" novel by Daniel O’Mahony.

TRANMETGURANS

Planet of Origin: Tranmetgura
Humanoid species which at the end of a long civil war, almost developed a unified planetary civilisation with the help of the Timelords before being invaded and harvested by the Hoothi some four billion years ago.
Source: Doctor Who “Love and War” novel