NA'VIS / PANDORANS / ALPHA CENTAURIANS

Planet of Origign: Pandora, a lush, Earth-like moon of the planet Polyphemus, in the Alpha Centauri system. Pandora itself has two moons. It was briefly colonised by humans in the 22th century but soon abandonned after an all-out revolt of the natives in 2154.
The Na’vis are a paleolithic species of blue skinned sapient humanoids with feline characteristics standing around 3 meters high. Their civilisationj is based on harmony with their ecosystem under a tribal structure. They live in large Hometrees and worship a mother goddess called Eywa. The Na'vis have tails whihc can be used as organic interface to bond with other lifeforms of the planet.

Source: James Cameron, Avatar

LAMETALIANS / RAMETALIANS

Planet of Origin: LaMetal. 
For millenias, the planet Lametall orbited the dark sun Ra. Ra followed an extremely large elliptical orbit which completed a revolution around the Sun in a 1,000 year period. Its orbit brought it, after a long journey in the far reaches of the outer solar system through the system's ecosphere. As far as it can be traced, by a capcrice of celestial mechanics, Ra was always hidden by Lametal from Earth's point of view. 
Circa 1999, the planet passed nearer to the Earth than it ever did before. Its atmosphere extended like a tail and fused with Earth’s atmosphere. This phenomenon, called the “Atmospheric Bridge” was short lived as  the “bridge” collapsed and disappeared 48 hours after LaMetal had started to move away from Earth. Their proximity to the Sun then slingshut Lametal and Ra out of the Solar system, heading toward the Andromeda galaxy.
Lametal is a planet with an air pressure, gravity, and atmospheric components which are roughly the same as Earth’s. However, it is much bigger. Observations vary as to its exact size. Some sources talk of a diameter of 109,404 km -about nine times Earth’s size- while other observations gave it only three times the size of the Earth. Those discrepencies in observations might be the result of visual distorsion caused by Ra's gravity well. It is known to be hollow with a moon-size core at its center. Its speed of rotation is 48 hours 22 minutes 43 seconds. 
The surface of the planet is usually covered by a thick layer of ice with a maximum extent of 3,000 meters. It is a bitterly cold world with a surface temperature of -280°C. 
During its time in the Solar System, each time it was coming near enough to the Sun, the ice melted, seas were born and cities buried underneath the ice began to appear, among them, the capital, Miyu City. The planet then knew a brief summer before its orbit brought it back toward the colder outer solar system. As it did, ice began to cover the planet again, starting at its poles and moving toward the equator.
After its departure from the Solar System, an orbital artificial sun was enginneered. It lasted  a thousand years before dying out. Then began the mechanisation of Lametal's population to ensure they could carry on in the depths of interstellar space. A civil insued, culminating with the destruction of the planet's outer shell. Luckily this happened as the planet was entering Euphrates, a binary star system locked in a fixed position halfway between the Milky Way and the Andromeda Galaxy. the inner core on which survivors had found shelter soon stabilised around Heavy Melder, one of the system's planet and became its moon.

Lametalians are humanoids looking much like Earth's humans but have much longer lifespans. They used to put themselves in hibernation while their planet was in the outer solar system, awakening only during their spring, as the planet was entering the inner system. At each passage of their world in the inner solar sytem, they had sent emissaries to Earth and had their planet not left the Solar System, they planned upon resettling on it. After its departure toward Andromeda. A plan was put in place to gradually transform the whole population into cyborgs in order for them to be able to survive in the intersideral void. When the planet's core put itself into Heavy Melder's orbit, the organics stayed while the mechanized ones continued toward Andromeda where they established themselves. 
It should be noted, as Lametal presumably gave birth to at least to a viable ecosystem and maybe a intelligent life (although it is dubious that human looking lifeforms would develop in parallel on both Earth and Lametal without any common origin whatsoever) that the planet was most probably in a much stabler orbit around the sun at one point, most presumably in the inner solar system, from which it has been torn at some point in the past.
It should also be noted that it took about a thousand years for the wandering Lametal to journey the 1,3 million light years separating the Solar System from the Euphrates star system which is halfway from the Milky Way to the Andromeda Galaxy; something that is physically impossible unless the planet was travelling faster than the speed of light or using shortcuts from point A to point B.
The two aforementionned points may be related to the presence of the black sun Ra in the vicinity of Lametal.

Lametal's Core, now orbiting Heavy Melder.

Source: Leiji Matsumoto, Queen Millenia TV series and film, Maetel Legend, Space Symphony Maetel.

NOO

The Noo is a consciousness that developed just after the Big Bang during Plank Time and encompassed all the universe until is was sealed outside of it by the laws of physics. At the dawn of the 4th Millenium AD a scientific expedition journeyed to the Hourglass Nebula and discovered the gate of Yedar, a passage leading to the dimension where Noo was bannished. The scientists were possessed by the Noo, which enabled it to interact with our universe. Its ultimate goal is to fully return to our universe by reclaiming a part of its original body-in this case, the Earth itself. The possessed warped the planet into an alternate dimension using a Density Serial Cannon. The space pirate Harlock tricked the Noo into shooting its ship the Arcadia with the weapon, allowing him to meet it on its own ground and restore the Earth.
Noo's influence on our dimension lies in creating fear in sentient beings and thereby enslaving their wills and driving them against one another.
Source: Leiji Matsumoto, Leijiverse, Endless Odyssey

FESA

The Fesa are an advanced alien species which developed space faring capacities some at some point between 1 and 10 million years ago and established themselves on Tschai, chasing the Gjee who had previsouly settled on the planet. They are said to have then fled the light of the red star Hsi (although it remains unclear what is meant by this assertion.)
Source: Jack Vance, Planet of Adventure, The Pnume

GJEE

The Gjee are an advanced alien species which developed space faring capacities some at some point between 1 and 10 million years ago and established themselves on Tschai where they founded eight empires beofre being expunged by the Fesa.
Source: Jack Vance, Planet of Adventure, The Pnume.

MONGOVIANS

Planet of Origin: Mongo, a rogue planet that passed through our solar system in 1933. Mongo is an inhospitable planet, with various extreme climate zones. Travelers to Mongo must pass through a "Death Zone" on the way, described as being "a zone devoid of any force". Mongo has at least two recognised moons, one of them being the planetoid Lunita. Mongo is approximately one of the diameter of earth but has a gravitational density that is only slightly less. It is a relatively young world with towering mountains not yet worn smooth by time and many areas of volcanic activity. Its vegetation is still limited to isolated areas of botanical giants.
Mongovians are humanoid looking much like Earht humans, with some subspecies having some morphological particularities such as lionmen and hawkmen.
In 1933, the mongovians were living under the control of a dictator, Emperor Ming. The people of Mongo had progressed scientifically beyond Earth. According to Ming, "the reason for our success is that we possess none of the human traits of kindness, mercy or pity! We are coldly scientific and ruthless!" The capital of Mongo is Minog City, also known as Nascent City. The main currency is the gold mingol. The area around the Emperor's palace is desolate and devoid of vegetation. Giant dragons live in the nearby caves. Other vicious animals of Mongo include monkey men, orangopoids and white-striped, bear-like animals.
The oceans of Mongo are home to giant sea life, including eels, sharks, water dragons and octosaks.
The planet is socially and geographically divided in several realms and the major ones are:
* Arboria is a forest principality governed by Prince Barin
* Frigia, a frozen kingdom ruled by Barin's cousin, Queen Fria,
* Coralia is an underwater kingdom beneath the Sea of Mystery. It is located east of Arboria and is ruled by Queen Undina,
* The Land of the Lion Men also borders the Sea of Mystery, and is ruled by King Jugrid and Prince Thun,
* The Magnetic Mountains are located east of the Land of the Lion Men and became the base of operations for Ming, after he was deposed
* The Sky City of the Hawk Men is located north of the Magnetic Mountains, and the leader of this realm is King Vultan,
* Tropica is a continent of forests. It is directly east of the Sky City. Queen Desira rules Tropica.
* The Fire Lands are located on the east coast of Tropica.

EUTERPIANS

Planet of Origin: Euterpe in the Milky Way Galaxy
Euterpians are a humanoid species of songsmiths who once travelled the Universe in ships piloted by sound waves. They became an space faring civilisation 150 millions years ago and became extinct about forty thousand years ago.
Source: DOctor WhoUniverse, Invasion of the Cat People

GRELD

The Greld were a sentient insectoid species which developed an advanced civilisation. They specialised in arms dealing. They had six legs and two pairs of crab-like claws, mottled dark red shells, four stalked eyes, and leathery wings.
They started a space faring civilisation about 150 millions years ago and participated in the Millennium War. (PDA: The Quantum Archangel)
In 1587, the Greld came to Earht in Virginia and implanted mind-control devices in the colonists who lived in there. In 1609, they used their mind-controlled humans in an attempt to destroy the Armageddon Convention, but were defeated. (MA: The Empire of Glass)
Their homeworld was destroyed by the humans in the late 2900ies (NA: Original Sin)
SOurce: DOctor Who Universe (See links above)

GREENIES / MEGARANS / DENEBIANS / JOVIANS

Planet of Origin: Megara, a world orbiting around Deneb / Denef
The Greenies are a sentient bipedal batracian species. They have developed an early industrial level civilisation. They are about four feet tall, brown or green skinned with webbed hands and feet, round heads with large globulous eyes, either black or yellow. Source: Edmund Hamilton, Captain Future, Captain Future and the Space Emperor (L'Empereur de l'Espace), Magic Moon (Silence, on tourne !)

M SPACE HUNTER NEBULA ALIENS / M宇宙ハンター星雲人, M UCHUU HANTA SEIUNJIN

Planet of Origin: a dying Earth-like planet in the M Space Hunter Nebula.

The M Space hunter Nebula Aliens are an insectoid species looking much like human-sized cockroacheswhich developed sentience and civilisation after the fall of the previous owner of their homeworld disappeared, leaving behind a dying planet, long plagued by pollution. It remains unknown if those previous inhabitants left the planet or became extinct but they were said to have been much closer to humans than the insectoids are. It also remains unknowns if they themsleves developed space faring technology or if they inherited it from their predecessors .

The insectoids made a desperate attempt to invade Earth in the 1970ies, disgused as humans and using the alien monsters Gigan and King Ghidorah they controled via technoloigcal means but their attempt was thwarted by the earth mutant monsters Godzilla and Anguirus. They later formed a deal with the seatopian human subculture living under the earth and showed them how to control the Gigan cyborg but with as disastrous results. The exact nature of their deal remains unknown.

Source: Toho Universe, Godzilla vs. Gigan (1972), Godzilla vs. Megalon (1973).

UNIDENTIFIED ALIEN TEAPOT / UFO

DORCONS

Planet of Origin; Dorca, in another galaxy of the Local Group, the same as Psychon.
The Dorcons are a humanoid species looking much like humand who have developed an expansive advances civilisation. They are conquerors who have built a vast interstellar empire. They have been known to have attacked Psychon in the past and use Psychon brain stem to achieve immortality.
Planet Entra and its lunar penal colony Ellna are probably part of the Dorcon empire.
Source: Space: 1999

PSYCHONS

Planet of Origin: Psychon (in another galaxy of the Local Group). Psychon had one moon, similar to Earth's one. As of the end of the second millenium, the planet has become geologically unstable.
Psychons are humanoids looking much like humand who developed an advanced civilisation and some space faring capacities. Some psychons are known to have developed psionic powers allowing them molecular transformation and/or mind control.
After attempted invasions by the Dorcons who abducted numbers of Psychons, the planet was left unstable. Either to find an new home or escape their aggressor, most of the inhabitants of the planet had left it by the beginning of the third millenium, leaving only the scientist Mentor and his daughter on the planet, trying to stabilise it with a biological computer named Psyche. Some escapees made contact with the Croton civilisation. Their insertion was complicated by the attempt by one of them to seize power through mind control.

Source: Space: 1999

UNAMED ALIEN OF THE DAY

An homemade aliens on sale for adoption in Lindsey Banker's Etsy shop.